main: port subcommands to mingw

Problem reported by Eli Zaretskii in
<http://lists.gnu.org/archive/html/bug-gnu-utils/2012-05/msg00013.html>.
Approach suggested by Bruno Haible as option (4) in
<http://lists.gnu.org/archive/html/bug-gnu-utils/2012-05/msg00036.html>.
* bootstrap.conf (gnulib_modules): Add system-quote.
* src/diff3.c, src/sdiff.c, src/util.c:
Include <system-quote.h>, not <sh-quote.h>.
* src/diff3.c (read_diff):
* src/sdiff.c (main, edit):
* src/util.c (begin_output):
Use system_quote_argv, for portability to Mingw.
* src/sdiff.c (NUM_SIGS, handler_index_of_SIGINT): Now enum
values, not macros; this is cleaner and avoids a GCC warning if
!HAVE_WORKING_VFORK.
* src/util.c (begin_output) [! HAVE_WORKING_FORK]: Do not use -f,
for consistency with the HAVE_WORKING_FORK code.

4 files changed, 33 insertions, 67 deletions

diff --git a/bootstrap.conf b/bootstrap.conf
index 55f0837..3954c4d 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -69,6 +69,7 @@ strftime
 strptime
 strtoumax
 sys_wait
+system-quote
 unistd
 unlocked-io
 update-copyright
diff --git a/src/diff3.c b/src/diff3.c
index 3b01071..e234401 100644
--- a/src/diff3.c
+++ b/src/diff3.c
@@ -29,7 +29,7 @@
 #include <file-type.h>
 #include <getopt.h>
 #include <progname.h>
-#include <sh-quote.h>
+#include <system-quote.h>
 #include <version-etc.h>
 #include <xalloc.h>
 #include <xfreopen.h>
@@ -1161,13 +1161,15 @@ read_diff (char const *filea,
   int fd, wstatus, status;
   int werrno = 0;
   struct stat pipestat;
-
-#if HAVE_WORKING_FORK
-
   char const *argv[9];
   char const **ap;
+#if HAVE_WORKING_FORK
   int fds[2];
   pid_t pid;
+#else
+  FILE *fpipe;
+  char *command;
+#endif
 
   ap = argv;
   *ap++ = diff_program;
@@ -1181,6 +1183,8 @@ read_diff (char const *filea,
   *ap++ = fileb;
   *ap = 0;
 
+#if HAVE_WORKING_FORK
+
   if (pipe (fds) != 0)
     perror_with_exit ("pipe");
 
@@ -1210,32 +1214,7 @@ read_diff (char const *filea,
 
 #else
 
-  FILE *fpipe;
-  char const args[] = " --horizon-lines=100 -- ";
-  char *command = xmalloc (shell_quote_length (diff_program)
-			   + sizeof "-a"
-			   + sizeof "--strip-trailing-cr"
-			   + sizeof args - 1
-			   + shell_quote_length (filea) + 1
-			   + shell_quote_length (fileb) + 1);
-  char *p = command;
-  p = shell_quote_copy (p, diff_program);
-  if (text)
-    {
-      strcpy (p, " -a");
-      p += 3;
-    }
-  if (strip_trailing_cr)
-    {
-      strcpy (p, " --strip-trailing-cr");
-      p += 20;
-    }
-  strcpy (p, args);
-  p += sizeof args - 1;
-  p = shell_quote_copy (p, filea);
-  *p++ = ' ';
-  p = shell_quote_copy (p, fileb);
-  *p = 0;
+  command = system_quote_argv (SCI_SYSTEM, (char **) argv);
   errno = 0;
   fpipe = popen (command, "r");
   if (!fpipe)
diff --git a/src/sdiff.c b/src/sdiff.c
index 63b2861..e82ec84 100644
--- a/src/sdiff.c
+++ b/src/sdiff.c
@@ -31,7 +31,7 @@
 #include <file-type.h>
 #include <getopt.h>
 #include <progname.h>
-#include <sh-quote.h>
+#include <system-quote.h>
 #include <version-etc.h>
 #include <xalloc.h>
 
@@ -66,7 +66,6 @@ static void perror_fatal (char const *) __attribute__((noreturn));
 static void trapsigs (void);
 static void untrapsig (int);
 
-#define NUM_SIGS (sizeof sigs / sizeof *sigs)
 static int const sigs[] = {
 #ifdef SIGHUP
        SIGHUP,
@@ -87,8 +86,12 @@ static int const sigs[] = {
        SIGPIPE,
 #endif
        SIGINT
-#define handler_index_of_SIGINT (NUM_SIGS - 1)
 };
+enum
+  {
+    NUM_SIGS = sizeof sigs / sizeof *sigs,
+    handler_index_of_SIGINT = NUM_SIGS - 1
+  };
 
 #if HAVE_SIGACTION
   /* Prefer 'sigaction' if available, since 'signal' can lose signals.  */
@@ -607,19 +610,7 @@ main (int argc, char *argv[])
 
 #if ! HAVE_WORKING_FORK
       {
-	size_t cmdsize = 1;
-	char *p, *command;
-	int i;
-
-	for (i = 0;  diffargv[i];  i++)
-	  cmdsize += shell_quote_length (diffargv[i]) + 1;
-	command = p = xmalloc (cmdsize);
-	for (i = 0;  diffargv[i];  i++)
-	  {
-	    p = shell_quote_copy (p, diffargv[i]);
-	    *p++ = ' ';
-	  }
-	p[-1] = 0;
+	char *command = system_quote_argv (SCI_SYSTEM, (char **) diffargv);
 	errno = 0;
 	diffout = popen (command, "r");
 	if (! diffout)
@@ -1020,16 +1011,17 @@ edit (struct line_filter *left, char const *lname, lin lline, lin llen,
 	    {
 	      int wstatus;
 	      int werrno = 0;
+	      char const *argv[3];
+
 	      ignore_SIGINT = true;
 	      checksigs ();
+	      argv[0] = editor_program;
+	      argv[1] = tmpname;
+	      argv[2] = 0;
 
 	      {
 #if ! HAVE_WORKING_FORK
-		char *command =
-		  xmalloc (shell_quote_length (editor_program)
-			   + 1 + strlen (tmpname) + 1);
-		sprintf (shell_quote_copy (command, editor_program),
-			 " %s", tmpname);
+		char *command = system_quote_argv (SCI_SYSTEM, (char **) argv);
 		wstatus = system (command);
 		if (wstatus == -1)
 		  werrno = errno;
@@ -1040,13 +1032,6 @@ edit (struct line_filter *left, char const *lname, lin lline, lin llen,
 		pid = fork ();
 		if (pid == 0)
 		  {
-		    char const *argv[3];
-		    int i = 0;
-
-		    argv[i++] = editor_program;
-		    argv[i++] = tmpname;
-		    argv[i] = 0;
-
 		    execvp (editor_program, (char **) argv);
 		    _exit (errno == ENOENT ? 127 : 126);
 		  }
diff --git a/src/util.c b/src/util.c
index 2b0bbbf..38b33ef 100644
--- a/src/util.c
+++ b/src/util.c
@@ -21,7 +21,7 @@
 #include "diff.h"
 #include <dirname.h>
 #include <error.h>
-#include <sh-quote.h>
+#include <system-quote.h>
 #include <xalloc.h>
 
 char const pr_program[] = PR_PROGRAM;
@@ -187,9 +187,16 @@ begin_output (void)
 
   if (paginate)
     {
+      char const *argv[4];
+
       if (fflush (stdout) != 0)
 	pfatal_with_name (_("write failed"));
 
+      argv[0] = pr_program;
+      argv[1] = "-h";
+      argv[2] = name;
+      argv[3] = 0;
+
       /* Make OUTFILE a pipe to a subsidiary 'pr'.  */
       {
 #if HAVE_WORKING_FORK
@@ -212,7 +219,7 @@ begin_output (void)
 		close (pipes[0]);
 	      }
 
-	    execl (pr_program, pr_program, "-h", name, (char *) 0);
+	    execv (pr_program, (char **) argv);
 	    _exit (errno == ENOENT ? 127 : 126);
 	  }
 	else
@@ -223,13 +230,7 @@ begin_output (void)
 	      pfatal_with_name ("fdopen");
 	  }
 #else
-	char *command = xmalloc (sizeof pr_program - 1 + 7
-				 + shell_quote_length (name) + 1);
-	char *p;
-	sprintf (command, "%s -f -h ", pr_program);
-	p = command + sizeof pr_program - 1 + 7;
-	p = shell_quote_copy (p, name);
-	*p = 0;
+	char *command = system_quote_argv (SCI_SYSTEM, (char **) argv);
 	errno = 0;
 	outfile = popen (command, "w");
 	if (!outfile)