misc: Update sources to more modern C

The code fails to build when having enabled (gcc) warnings:
   -Werror=implicit
   -Werror=implicit-function-declaration
   -Werror=implicit-int
   -Werror=int-conversion
   -Werror=old-style-definition
   -Werror=strict-prototypes

24 files changed, 110 insertions, 111 deletions

diff --git a/examples/access_components.c b/examples/access_components.c
index 0fbc3945..726d5cce 100644
--- a/examples/access_components.c
+++ b/examples/access_components.c
@@ -24,7 +24,7 @@ void do_something(icalcomponent *c);
 
 */
 
-icalcomponent* create_new_component()
+icalcomponent* create_new_component(void)
 {
 
     /* variable definitions */
@@ -193,7 +193,7 @@ icalcomponent* create_new_component()
 /* Now, create the same component as in the previous routine, but use
 the constructor style. */
 
-icalcomponent* create_new_component_with_va_args()
+icalcomponent* create_new_component_with_va_args(void)
 {
 
     /* This is a similar set up to the last routine */
diff --git a/examples/access_properties_and_parameters.c b/examples/access_properties_and_parameters.c
index 1f0f92f1..04df481a 100644
--- a/examples/access_properties_and_parameters.c
+++ b/examples/access_properties_and_parameters.c
@@ -99,7 +99,7 @@ void update_attendees(icalcomponent* event)
 
 /* Here are some examples of manipulating properties */
 
-void test_properties()
+void test_properties(void)
 {
     icalproperty *prop;
     icalparameter *param;
diff --git a/examples/errors.c b/examples/errors.c
index 25bccfdd..8952cb7c 100644
--- a/examples/errors.c
+++ b/examples/errors.c
@@ -2,7 +2,7 @@
 
 #include <libical/ical.h>
 
-void program_errors()
+void program_errors(void)
 {
     /*Most routines will set icalerrno on errors. This is an
       enumeration defined in icalerror.h */
diff --git a/examples/main.c b/examples/main.c
index 587dbd21..3f7c78e0 100644
--- a/examples/main.c
+++ b/examples/main.c
@@ -1,7 +1,7 @@
 /* This is just to make the code in the example directory link properly. */
 #include <libical/ical.h>
 
-int main()
+int main(void)
 {
     return 1;
 }
diff --git a/src/libical-glib/tools/generator.c b/src/libical-glib/tools/generator.c
index 694c5fd0..f178ec9d 100644
--- a/src/libical-glib/tools/generator.c
+++ b/src/libical-glib/tools/generator.c
@@ -1921,7 +1921,7 @@ gchar *get_true_type(const gchar *type)
     return res;
 }
 
-static void initialize_default_value_table()
+static void initialize_default_value_table(void)
 {
     defaultValues = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, g_free);
     (void)g_hash_table_insert(defaultValues, g_strdup("gboolean"), g_strdup("FALSE"));
diff --git a/src/libical-glib/tools/xml-parser.c b/src/libical-glib/tools/xml-parser.c
index a9cf2704..d3fdd44c 100644
--- a/src/libical-glib/tools/xml-parser.c
+++ b/src/libical-glib/tools/xml-parser.c
@@ -15,7 +15,7 @@
 
 #include "xml-parser.h"
 
-Structure *structure_new()
+Structure *structure_new(void)
 {
     Structure *structure;
 
@@ -74,7 +74,7 @@ void structure_free(Structure * structure)
     g_free(structure);
 }
 
-Declaration *declaration_new()
+Declaration *declaration_new(void)
 {
     Declaration *declaration = g_new0(Declaration, 1);
 
@@ -98,7 +98,7 @@ void declaration_free(Declaration * declaration)
     g_free(declaration);
 }
 
-Method *method_new()
+Method *method_new(void)
 {
     Method *method;
 
@@ -141,7 +141,7 @@ void method_free(Method * method)
     g_free(method);
 }
 
-Parameter *parameter_new()
+Parameter *parameter_new(void)
 {
     Parameter *parameter;
 
@@ -184,7 +184,7 @@ void parameter_free(Parameter * para)
     g_free(para);
 }
 
-Ret *ret_new()
+Ret *ret_new(void)
 {
     Ret *ret;
 
@@ -222,7 +222,7 @@ void ret_free(Ret * ret)
     g_free(ret);
 }
 
-Enumeration *enumeration_new()
+Enumeration *enumeration_new(void)
 {
     Enumeration *enumeration = g_new0(Enumeration, 1);
 
diff --git a/src/libical-glib/tools/xml-parser.h b/src/libical-glib/tools/xml-parser.h
index bccbb4d3..bffb5a17 100644
--- a/src/libical-glib/tools/xml-parser.h
+++ b/src/libical-glib/tools/xml-parser.h
@@ -83,17 +83,17 @@ typedef struct Enumeration {
     gchar *comment;
 } Enumeration;
 
-Structure *structure_new();
+Structure *structure_new(void);
 void structure_free(Structure *structure);
-Method *method_new();
+Method *method_new(void);
 void method_free(Method *method);
-Parameter *parameter_new();
+Parameter *parameter_new(void);
 void parameter_free(Parameter *para);
-Ret *ret_new();
+Ret *ret_new(void);
 void ret_free(Ret *ret);
-Enumeration *enumeration_new();
+Enumeration *enumeration_new(void);
 void enumeration_free(Enumeration *enumeration);
-Declaration *declaration_new();
+Declaration *declaration_new(void);
 void declaration_free(Declaration *declaration);
 
 GList *get_list_from_string(const gchar *str);
diff --git a/src/libical/caldate.c b/src/libical/caldate.c
index e26926b4..f3d600c2 100644
--- a/src/libical/caldate.c
+++ b/src/libical/caldate.c
@@ -55,8 +55,7 @@
  *
  */
 
-long caldat( date )
-struct ut_instant * date;
+long caldat( struct ut_instant * date )
 {
 	double frac;
 	long jd;
@@ -129,8 +128,7 @@ struct ut_instant * date;
  *	50 Year canon of solar eclipses: 1986-2035
  */
 
-double juldat( date )
-struct ut_instant * date;
+double juldat( struct ut_instant * date )
 {
 	double frac, gyr;
 	long iy0, im0;
diff --git a/src/libical/icalduration.c b/src/libical/icalduration.c
index d142c0d5..3f9516da 100644
--- a/src/libical/icalduration.c
+++ b/src/libical/icalduration.c
@@ -301,7 +301,7 @@ int icaldurationtype_is_null_duration(struct icaldurationtype d)
    following the philosophy of unix errno. we set the is_neg
    to -1 to indicate that this is a bad duration.
 */
-struct icaldurationtype icaldurationtype_bad_duration()
+struct icaldurationtype icaldurationtype_bad_duration(void)
 {
     struct icaldurationtype d;
 
diff --git a/src/libical/icalerror.c b/src/libical/icalerror.c
index e10fd72e..e6081c2b 100644
--- a/src/libical/icalerror.c
+++ b/src/libical/icalerror.c
@@ -92,7 +92,7 @@ void icalerror_crash_here(void)
     assert(*p);
 }
 
-void icalerror_clear_errno()
+void icalerror_clear_errno(void)
 {
     icalerrno = ICAL_NO_ERROR;
 }
@@ -108,7 +108,7 @@ void icalerror_set_errors_are_fatal(int fatal)
     icalerror_errors_are_fatal = (fatal != 0);
 }
 
-int icalerror_get_errors_are_fatal()
+int icalerror_get_errors_are_fatal(void)
 {
     return icalerror_errors_are_fatal;
 }
diff --git a/src/libical/icalmemory.c b/src/libical/icalmemory.c
index 6c1bd9ca..db4fe4ea 100644
--- a/src/libical/icalmemory.c
+++ b/src/libical/icalmemory.c
@@ -224,7 +224,7 @@ void *icalmemory_tmp_buffer(size_t size)
     return buf;
 }
 
-void icalmemory_free_ring()
+void icalmemory_free_ring(void)
 {
     buffer_ring *br;
 
diff --git a/src/libical/pvl.c b/src/libical/pvl.c
index 960941a7..726ff835 100644
--- a/src/libical/pvl.c
+++ b/src/libical/pvl.c
@@ -76,7 +76,7 @@ typedef struct pvl_list_t
  * @return  Pointer to the new list, 0 if there is no available memory.
  */
 
-pvl_list pvl_newlist()
+pvl_list pvl_newlist(void)
 {
     struct pvl_list_t *L;
 
diff --git a/src/libicalss/icalsslexer.c b/src/libicalss/icalsslexer.c
index f889016c..ac3a2ab7 100644
--- a/src/libicalss/icalsslexer.c
+++ b/src/libicalss/icalsslexer.c
@@ -1961,7 +1961,7 @@ void ssfree (void * ptr )
 
 
 
-int sswrap()
+int sswrap(void)
 {
      return 1;
 }
diff --git a/src/libicalvcal/vcc.c b/src/libicalvcal/vcc.c
index 19eb9a16..97632198 100644
--- a/src/libicalvcal/vcc.c
+++ b/src/libicalvcal/vcc.c
@@ -444,7 +444,7 @@ static int pushVObject(const char *prop)
 
 
 /* This pops the recently built vCard off the stack and returns it. */
-static VObject* popVObject()
+static VObject* popVObject(void)
     {
     VObject *oldObj;
     if (ObjStackTop < 0) {
@@ -577,7 +577,7 @@ static int lexWithinMode(enum LexMode mode) {
     return 0;
     }
 
-static char lexGetc_()
+static char lexGetc_(void)
     {
     /* get next char from input, no buffering. */
     if (lexBuf.curPos == lexBuf.inputLen)
@@ -594,7 +594,7 @@ static char lexGetc_()
         }
     }
 
-static int lexGeta()
+static int lexGeta(void)
     {
     ++lexBuf.len;
     return (lexBuf.buf[lexBuf.getPtr] = lexGetc_());
@@ -606,7 +606,7 @@ static int lexGeta_(int i)
     return (lexBuf.buf[(lexBuf.getPtr+i)%MAX_LEX_LOOKAHEAD] = lexGetc_());
     }
 
-static void lexSkipLookahead() {
+static void lexSkipLookahead(void) {
     if (lexBuf.len > 0 && lexBuf.buf[lexBuf.getPtr]!=((char) EOF)) {
         /* don't skip EOF. */
         lexBuf.getPtr = (lexBuf.getPtr + 1) % MAX_LEX_LOOKAHEAD;
@@ -614,7 +614,7 @@ static void lexSkipLookahead() {
         }
     }
 
-static int lexLookahead() {
+static int lexLookahead(void) {
     int c = (lexBuf.len)?
         lexBuf.buf[lexBuf.getPtr]:
         lexGeta();
@@ -640,7 +640,7 @@ static int lexLookahead() {
     return c;
     }
 
-static int lexGetc() {
+static int lexGetc(void) {
     int c = lexLookahead();
     if (lexBuf.len > 0 && lexBuf.buf[lexBuf.getPtr]!=((char) EOF)) {
         /* EOF will remain in lookahead buffer */
@@ -650,14 +650,14 @@ static int lexGetc() {
     return c;
     }
 
-static void lexSkipLookaheadWord() {
+static void lexSkipLookaheadWord(void) {
     if (lexBuf.strsLen <= lexBuf.len) {
         lexBuf.len -= lexBuf.strsLen;
         lexBuf.getPtr = (lexBuf.getPtr + lexBuf.strsLen) % MAX_LEX_LOOKAHEAD;
         }
     }
 
-static void lexClearToken()
+static void lexClearToken(void)
     {
     lexBuf.strsLen = 0;
     }
@@ -675,11 +675,11 @@ static void lexAppendc(int c)
         }
     }
 
-static char* lexStr() {
+static char* lexStr(void) {
     return dupStr(lexBuf.strs,(size_t)lexBuf.strsLen+1);
     }
 
-static void lexSkipWhite() {
+static void lexSkipWhite(void) {
     int c = lexLookahead();
     while (c == ' ' || c == '\t') {
         lexSkipLookahead();
@@ -687,7 +687,7 @@ static void lexSkipWhite() {
         }
     }
 
-static char* lexGetWord() {
+static char* lexGetWord(void) {
     int c;
     lexSkipWhite();
     lexClearToken();
@@ -712,7 +712,7 @@ static void lexPushLookaheadc(int c) {
     lexBuf.len += 1;
     }
 
-static char* lexLookaheadWord() {
+static char* lexLookaheadWord(void) {
     /* this function can lookahead word with max size of MAX_LEX_LOOKAHEAD_0
      /  and thing bigger than that will stop the lookahead and return 0;
      / leading white spaces are not recoverable.
@@ -778,7 +778,7 @@ static void handleMoreRFC822LineBreak(int c) {
         }
     }
 
-static char* lexGet1Value() {
+static char* lexGet1Value(void) {
     int c;
     lexSkipWhite();
     c = lexLookahead();
@@ -849,7 +849,7 @@ void initLex(const char *inputstring, unsigned long inputlen, FILE *inputfile)
 
     }
 
-static void finiLex() {
+static void finiLex(void) {
     VObject* vobj, *topobj = 0;
     while(vobj = popVObject(), vobj) {
         topobj = vobj;
@@ -863,7 +863,7 @@ static void finiLex() {
 /* This parses and converts the base64 format for binary encoding into
  * a decoded buffer (allocated with new).  See RFC 1521.
  */
-static char * lexGetDataFromBase64()
+static char * lexGetDataFromBase64(void)
     {
     size_t bytesLen = 0, bytesMax = 0;
     int quadIx = 0, pad = 0;
@@ -985,7 +985,7 @@ static int match_begin_end_name(int end) {
     return 0;
     }
 
-static char* lexGetQuotedPrintable()
+static char* lexGetQuotedPrintable(void)
     {
     char cur;
 
@@ -1042,7 +1042,7 @@ EndString:
     return lexStr();
     } /* LexQuotedPrintable */
 
-int yylex() {
+int yylex(void) {
 
     int lexmode = LEXMODE();
     if (lexmode == L_VALUES) {
@@ -1160,7 +1160,7 @@ int yylex() {
 /***                                                    Public Functions                                                ****/
 /***************************************************************************/
 
-static VObject* Parse_MIMEHelper()
+static VObject* Parse_MIMEHelper(void)
     {
     ObjStackTop = -1;
     mime_numErrors = 0;
diff --git a/src/libicalvcal/vobject.c b/src/libicalvcal/vobject.c
index 10d0cf5a..03a4249c 100644
--- a/src/libicalvcal/vobject.c
+++ b/src/libicalvcal/vobject.c
@@ -682,7 +682,7 @@ void unUseStr(const char *s)
     }
 }
 
-void cleanStrTbl()
+void cleanStrTbl(void)
 {
     int i;
     for (i=0; i<STRTBLSIZE;i++) {
diff --git a/src/libicalvcal/vobject.h b/src/libicalvcal/vobject.h
index 7541be58..ca3317ca 100644
--- a/src/libicalvcal/vobject.h
+++ b/src/libicalvcal/vobject.h
@@ -297,7 +297,7 @@ extern "C"
     LIBICAL_VCAL_EXPORT char *writeMemVObjects(char *s, int *len, VObject *list);
 
     LIBICAL_VCAL_EXPORT const char *lookupStr(const char *s);
-    LIBICAL_VCAL_EXPORT void cleanStrTbl();
+    LIBICAL_VCAL_EXPORT void cleanStrTbl(void);
 
     LIBICAL_VCAL_EXPORT void cleanVObject(VObject *o);
     LIBICAL_VCAL_EXPORT void cleanVObjects(VObject *list);
diff --git a/src/test/builtin_timezones.c b/src/test/builtin_timezones.c
index 3ceb462d..c6c22012 100644
--- a/src/test/builtin_timezones.c
+++ b/src/test/builtin_timezones.c
@@ -80,7 +80,7 @@ static void test_get_component_threadsafety(void)
 }
 #endif
 
-int main()
+int main(void)
 {
     icalarray *builtin_timezones;
     icaltimetype tt;
diff --git a/src/test/icaltm_test.c b/src/test/icaltm_test.c
index 141d49e4..0df024a2 100644
--- a/src/test/icaltm_test.c
+++ b/src/test/icaltm_test.c
@@ -27,11 +27,12 @@
 
 static icaltimezone *zone, *utc;
 
-static void *test_tread()
+static void *test_tread(void *user_data)
 {
     struct icaltimetype itt;
     int ii;
 
+    _unused(user_data);
     itt = icaltime_from_string("19710203T040506");
     itt.zone = zone;
 
@@ -42,7 +43,7 @@ static void *test_tread()
     return NULL;
 }
 
-int main()
+int main(void)
 {
     pthread_t thread[2];
     int ii;
diff --git a/src/test/regression-component.c b/src/test/regression-component.c
index 2df42abc..f3f97e25 100644
--- a/src/test/regression-component.c
+++ b/src/test/regression-component.c
@@ -83,7 +83,7 @@ static const char *create_new_component_str =
     "LOCATION:1CP Conference Room 4350\r\n" "END:VEVENT\r\n" "END:VCALENDAR\r\n";
 
 /* Create a new component */
-void create_new_component()
+void create_new_component(void)
 {
     icalcomponent *calendar;
     icalcomponent *timezone;
@@ -213,7 +213,7 @@ void create_new_component()
 
 /* Create a new component, using the va_args list */
 
-void create_new_component_with_va_args()
+void create_new_component_with_va_args(void)
 {
     icalcomponent *calendar;
     struct icaltimetype atime = icaltime_from_timet_with_zone(time(0), 0, NULL);
@@ -308,7 +308,7 @@ static void print_span(int c, struct icaltime_span span)
 /** Test icalcomponent_get_span()
  *
  */
-void test_icalcomponent_get_span()
+void test_icalcomponent_get_span(void)
 {
     time_t tm1 = 973378800;     /*Sat Nov  4 23:00:00 UTC 2000,
                                    Sat Nov  4 15:00:00 PST 2000 */
diff --git a/src/test/regression-recur.c b/src/test/regression-recur.c
index e11112e6..632c910e 100644
--- a/src/test/regression-recur.c
+++ b/src/test/regression-recur.c
@@ -75,7 +75,7 @@ static void recur_callback(icalcomponent *comp, struct icaltime_span *span, void
     *num_recurs = *num_recurs + 1;
 }
 
-void test_recur_file()
+void test_recur_file(void)
 {
     icalset *cin = 0;
     struct icaltimetype next;
diff --git a/src/test/regression-storage.c b/src/test/regression-storage.c
index eb11f6d5..b1edc6df 100644
--- a/src/test/regression-storage.c
+++ b/src/test/regression-storage.c
@@ -283,7 +283,7 @@ void test_fileset_extended(void)
    DB file), and keys for storage and retrieval.
 */
 
-void test_bdbset()
+void test_bdbset(void)
 {
     icalset *cout;
     int month = 0;
diff --git a/src/test/regression.c b/src/test/regression.c
index 0d40f028..24997d8d 100644
--- a/src/test/regression.c
+++ b/src/test/regression.c
@@ -171,7 +171,7 @@ static char** get_required_attendees(icalcomponent* event)
     }
   */
 
-void test_values()
+void test_values(void)
 {
     icalvalue *v;
     icalvalue *copy;
@@ -280,7 +280,7 @@ void test_values()
     icalerror_set_error_state(ICAL_MALFORMEDDATA_ERROR, ICAL_ERROR_DEFAULT);
 }
 
-void test_properties()
+void test_properties(void)
 {
     icalproperty *prop;
     icalparameter *param;
@@ -337,7 +337,7 @@ void test_properties()
         icalproperty_free(prop);
 }
 
-void test_utf8()
+void test_utf8(void)
 {
     icalcomponent *comp;
     icalproperty *prop;
@@ -414,7 +414,7 @@ void test_utf8()
     icalcomponent_free(comp);
 }
 
-void test_icaltime_compare_utc_zone()
+void test_icaltime_compare_utc_zone(void)
 {
     struct icaltimetype a;
     struct icaltimetype b;
@@ -431,7 +431,7 @@ void test_icaltime_compare_utc_zone()
     int_is("a < b", icaltime_compare(a, b), -1);
 }
 
-void test_parameters()
+void test_parameters(void)
 {
     icalparameter *p;
     int i;
@@ -506,7 +506,7 @@ const char *bad_child =
     "TZNAME:\\r\n"
     "TZNAME:\\r\n";
 
-void test_components()
+void test_components(void)
 {
     icalcomponent *c;
     icalcomponent *child;
@@ -596,7 +596,7 @@ int test_component_foreach_parameterized(int startOffsSec, int endOffsSec, int e
     return 0;
 }
 
-void test_component_foreach()
+void test_component_foreach(void)
 {
     const char *calStr =
         "BEGIN:VCALENDAR\n"
@@ -700,7 +700,7 @@ void test_component_foreach()
     }
 }
 
-void test_recur_iterator_set_start()
+void test_recur_iterator_set_start(void)
 {
     icaltimetype start = icaltime_from_string("20150526");
     struct icalrecurrencetype recurrence = icalrecurrencetype_from_string("FREQ=WEEKLY");
@@ -712,7 +712,7 @@ void test_recur_iterator_set_start()
     icalrecur_iterator_free(iterator);
 }
 
-void test_recur_iterator_on_jan_1()
+void test_recur_iterator_on_jan_1(void)
 {
     icaltimetype start = icaltime_from_string("20190101");
     struct icalrecurrencetype recurrence = icalrecurrencetype_from_string("FREQ=WEEKLY;WKST=SU;INTERVAL=2;BYDAY=MO,TU,WE,TH,FR");
@@ -726,7 +726,7 @@ void test_recur_iterator_on_jan_1()
     icalrecur_iterator_free(iterator);
 }
 
-void test_memory()
+void test_memory(void)
 {
     size_t bufsize = 256;
     int i;
@@ -902,7 +902,7 @@ void test_memory()
     }
 }
 
-void test_dirset()
+void test_dirset(void)
 {
     icalcomponent *c;
     icalgauge *gauge;
@@ -1022,7 +1022,7 @@ void test_dirset()
     icalset_free(cluster);
 }
 
-void test_compare()
+void test_compare(void)
 {
     icalvalue *v1, *v2;
 
@@ -1077,7 +1077,7 @@ void test_compare()
     icalvalue_free(v2);
 }
 
-void test_restriction()
+void test_restriction(void)
 {
     icalcomponent *comp;
     struct icaltimetype atime = icaltime_from_timet_with_zone(time(0), 0, NULL);
@@ -1148,7 +1148,7 @@ void test_restriction()
     ok("icalrestriction_check() == 0", (valid == 0));
 }
 
-void test_calendar()
+void test_calendar(void)
 {
     icalcomponent *comp;
     icalset *c;
@@ -1225,7 +1225,7 @@ void print_occur(struct icalrecurrencetype recur, struct icaltimetype start)
     icalrecur_iterator_free(ritr);
 }
 
-void test_recur()
+void test_recur(void)
 {
     struct icalrecurrencetype rt;
     struct icaltimetype start;
@@ -1256,7 +1256,7 @@ void test_recur()
 /*    test_increment();*/
 }
 
-void test_expand_recurrence()
+void test_expand_recurrence(void)
 {
     time_t arr[10];
     time_t now = 931057385;
@@ -1289,7 +1289,7 @@ enum byrule
     BY_SET_POS
 };
 
-void icalrecurrencetype_test()
+void icalrecurrencetype_test(void)
 {
     icalvalue *v =
         icalvalue_new_from_string(
@@ -1319,7 +1319,7 @@ void icalrecurrencetype_test()
 }
 
 /* From Federico Mena Quintero <federico@ximian.com>    */
-void test_recur_parameter_bug()
+void test_recur_parameter_bug(void)
 {
     static const char test_icalcomp_str[] =
         "BEGIN:VEVENT\r\n"
@@ -1367,7 +1367,7 @@ void test_recur_parameter_bug()
     icalcomponent_free(icalcomp);
 }
 
-void test_duration()
+void test_duration(void)
 {
     struct icaldurationtype d;
 
@@ -1450,7 +1450,7 @@ void test_duration()
     str_is("P51DT5H", icaldurationtype_as_ical_string(d), "P51DT5H");
 }
 
-void test_period()
+void test_period(void)
 {
     struct icalperiodtype p;
     icalvalue *v;
@@ -1472,7 +1472,7 @@ void test_period()
     icalvalue_free(v);
 }
 
-void test_strings()
+void test_strings(void)
 {
     icalvalue *v;
 
@@ -1495,7 +1495,7 @@ void test_strings()
 }
 
 /* Check RFC6868 encoding of "unsafe" chars in parameter values, such as '\n' */
-void test_tzid_escape()
+void test_tzid_escape(void)
 {
     icalparameter *tzid;
     icalproperty *prop;
@@ -1514,7 +1514,7 @@ void test_tzid_escape()
     icalproperty_free(prop);
 }
 
-void test_requeststat()
+void test_requeststat(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -1626,7 +1626,7 @@ void test_requeststat()
     icalcomponent_free(c);
 }
 
-void test_dtstart()
+void test_dtstart(void)
 {
     struct icaltimetype tt, tt2;
 
@@ -2011,7 +2011,7 @@ void do_test_time(const char *zone)
            0);
 }
 
-void test_iterators()
+void test_iterators(void)
 {
     icalcomponent *c, *inner, *next;
     icalcompiter i;
@@ -2129,7 +2129,7 @@ void test_iterators()
     icalcomponent_free(c);
 }
 
-void test_time()
+void test_time(void)
 {
     const char *zones[6] =
     {
@@ -2149,7 +2149,7 @@ void test_time()
     }
 }
 
-void test_icalset()
+void test_icalset(void)
 {
     icalcomponent *c;
 
@@ -2174,7 +2174,7 @@ void test_icalset()
     icalset_free(d);
 }
 
-void test_overlaps()
+void test_overlaps(void)
 {
     icalcomponent *cset, *c;
     icalset *set;
@@ -2251,7 +2251,7 @@ void test_overlaps()
         icalcomponent_free(c);
 }
 
-void test_fblist()
+void test_fblist(void)
 {
     icalspanlist *sl, *new_sl;
     icalfileset_options options = { O_RDONLY, 0644, 0, NULL };
@@ -2387,7 +2387,7 @@ void test_fblist()
     icalset_free(set);
 }
 
-void test_convenience()
+void test_convenience(void)
 {
     icalcomponent *c;
     int duration;
@@ -2553,7 +2553,7 @@ void test_convenience()
     icalcomponent_free(c);
 }
 
-void test_time_parser()
+void test_time_parser(void)
 {
     struct icaltimetype tt;
 
@@ -2586,7 +2586,7 @@ void test_time_parser()
     icalerror_set_errors_are_fatal(1);
 }
 
-void test_recur_parser()
+void test_recur_parser(void)
 {
     struct icalrecurrencetype rt;
     icalvalue *v = NULL;
@@ -2629,7 +2629,7 @@ char *ical_strstr(const char *haystack, const char *needle)
     return strstr(haystack, needle);
 }
 
-void test_start_of_week()
+void test_start_of_week(void)
 {
     struct icaltimetype tt2;
     struct icaltimetype tt1 = icaltime_from_string("19900110");
@@ -2663,7 +2663,7 @@ void test_start_of_week()
     } while (tt1.year < 2010);
 }
 
-void test_doy()
+void test_doy(void)
 {
     struct icaltimetype tt1, tt2;
     short doy, doy2;
@@ -2760,7 +2760,7 @@ void test_doy()
     ok("day of year == 60", (doy == 60));
 }
 
-void test_x()
+void test_x(void)
 {
     static const char test_icalcomp_str[] =
         "BEGIN:VEVENT\r\n"
@@ -2807,7 +2807,7 @@ void test_x()
     icalcomponent_free(icalcomp);
 }
 
-void test_gauge_sql()
+void test_gauge_sql(void)
 {
     icalgauge *g;
     const char *str;
@@ -2860,7 +2860,7 @@ void test_gauge_sql()
     icalgauge_free(g);
 }
 
-void test_gauge_compare()
+void test_gauge_compare(void)
 {
     icalgauge *g;
     icalcomponent *c;
@@ -3160,7 +3160,7 @@ icalcomponent *make_component(int i)
     return c;
 }
 
-void test_fileset()
+void test_fileset(void)
 {
 #if defined(HAVE_UNLINK)
     icalset *fs;
@@ -3243,7 +3243,7 @@ void microsleep(int us)
 #endif /*Windows Sleep is useless for microsleeping */
 }
 
-void test_file_locks()
+void test_file_locks(void)
 {
 #if defined(HAVE_WAITPID) && defined(HAVE_FORK) && defined(HAVE_UNLINK)
     pid_t pid;
@@ -3376,7 +3376,7 @@ void test_file_locks()
 #endif
 }
 
-void test_action()
+void test_action(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3416,7 +3416,7 @@ void test_action()
     icalcomponent_free(c);
 }
 
-void test_trigger()
+void test_trigger(void)
 {
     struct icaltriggertype tr;
     icalcomponent *c;
@@ -3539,7 +3539,7 @@ void test_trigger()
     icalproperty_free(p);
 }
 
-void test_rdate()
+void test_rdate(void)
 {
     struct icaldatetimeperiodtype dtp;
     icalproperty *p;
@@ -3632,7 +3632,7 @@ void test_rdate()
     icalproperty_free(p);
 }
 
-void test_langbind()
+void test_langbind(void)
 {
     icalcomponent *c, *inner;
     icalproperty *p;
@@ -3707,7 +3707,7 @@ void test_langbind()
     icalcomponent_free(c);
 }
 
-void test_property_parse()
+void test_property_parse(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3746,7 +3746,7 @@ void test_property_parse()
     icalcomponent_free(c);
 }
 
-void test_value_parameter()
+void test_value_parameter(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3778,7 +3778,7 @@ void test_value_parameter()
     icalcomponent_free(c);
 }
 
-void test_empty_parameter()
+void test_empty_parameter(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3806,7 +3806,7 @@ void test_empty_parameter()
     icalcomponent_free(c);
 }
 
-void test_x_parameter()
+void test_x_parameter(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3842,7 +3842,7 @@ void test_x_parameter()
     icalcomponent_free(c);
 }
 
-void test_x_property()
+void test_x_property(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3867,7 +3867,7 @@ void test_x_property()
     icalcomponent_free(c);
 }
 
-void test_utcoffset()
+void test_utcoffset(void)
 {
     icalcomponent *c;
 
@@ -3884,7 +3884,7 @@ void test_utcoffset()
         icalcomponent_free(c);
 }
 
-void test_attach()
+void test_attach(void)
 {
     icalcomponent *c;
 
@@ -3904,7 +3904,7 @@ void test_attach()
         icalcomponent_free(c);
 }
 
-void test_attach_caldav()
+void test_attach_caldav(void)
 {
     icalcomponent *c;
     icalproperty *p;
@@ -3961,7 +3961,7 @@ void test_attach_caldav()
         icalcomponent_free(c);
 }
 
-void test_attach_url()
+void test_attach_url(void)
 {
     static const char test_icalcomp_str_attachwithurl[] =
         "BEGIN:VALARM\r\n" "ATTACH:foofile\r\n" "END:VALARM\r\n";
@@ -3990,7 +3990,7 @@ static void test_free_attach_data(char *data, void *user_data)
     (*pbeen_called)++;
 }
 
-void test_attach_data()
+void test_attach_data(void)
 {
     static const char test_icalcomp_str_attachwithdata[] =
         "BEGIN:VALARM\r\n" "ATTACH;VALUE=BINARY:foofile\r\n" "END:VALARM\r\n";
diff --git a/src/test/regression.h b/src/test/regression.h
index 9c5aab88..88a29509 100644
--- a/src/test/regression.h
+++ b/src/test/regression.h
@@ -66,7 +66,7 @@ extern "C"
     void test_header(const char *title, int test_set);
     void test_start(int);
     int test_end(void);
-    void test_run(const char *test_name, void (*test_fcn) (), int do_test, int headeronly);
+    void test_run(const char *test_name, void (*test_fcn) (void), int do_test, int headeronly);
 
 #ifdef  __cplusplus
 }
diff --git a/src/test/timezones.c b/src/test/timezones.c
index 935e912d..6beff2f9 100644
--- a/src/test/timezones.c
+++ b/src/test/timezones.c
@@ -26,7 +26,7 @@
 
 #define MAX_FAILURE_RATE 1
 
-int main()
+int main(void)
 {
     icalarray *timezones;
     icaltimezone *zone, *utc_zone;