maint: use to_uchar function rather than explicit casts

* src/system.h (to_uchar): Define function.
* src/kwsearch.c (Fexecute): Use to_uchar twice in place of casts.
* src/dfasearch.c (EGexecute): Likewise.
* src/main.c (prepend_args): Likewise.
* src/kwset.c (U): Define in terms of to_uchar.
* src/dfa.c (match_mb_charset): Use to_uchar, not an explicit cast.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/system.h b/src/system.h
index b07471b3..4c854096 100644
--- a/src/system.h
+++ b/src/system.h
@@ -55,4 +55,13 @@ enum { EXIT_TROUBLE = 2 };
 
 #define STREQ(a, b) (strcmp (a, b) == 0)
 
+/* Convert a possibly-signed character to an unsigned character.  This is
+   a bit safer than casting to unsigned char, since it catches some type
+   errors that the cast doesn't.  */
+static inline unsigned char
+to_uchar (char ch)
+{
+  return ch;
+}
+
 #endif