Don't use -Wpointer-arith if it produces excessive warnings

[Mike McCormack <mike@codeweavers.com>]

On Slackware 8.1, this caused a screenful of warnings for *every* file 
compiled, which makes it difficult to see important warnings.

Mike


ChangeLog:
* Turn off -Wpointer-arith if it generates warnings when including string.h.
Index: configure.ac
===================================================================
RCS file: /home/wine/wine/configure.ac,v
retrieving revision 1.126
diff -u -r1.126 configure.ac
--- configure.ac	24 Jan 2003 01:08:15 -0000	1.126
+++ configure.ac	23 Feb 2003 22:03:49 -0000
@@ -634,11 +634,28 @@
     AC_DEFINE(_FILE_OFFSET_BITS, 64, [Set this to 64 to enable 64-bit file support on Linux])
 fi
 
+dnl *** Check for noisy string.h ***
+
+OLD_CFLAGS=$CFLAGS
+CFLAGS="$CFLAGS -Wpointer-arith -pedantic-errors"
+AC_CACHE_CHECK([string.h that generates warings], ac_string_h_warnings,
+      AC_TRY_COMPILE( [#include <string.h>],
+		[;],
+                [ac_string_h_warnings=no],
+                [ac_string_h_warnings=yes]
+	      )
+)
+CFLAGS=$OLD_CFLAGS
+if test "$ac_string_h_warnings" = "no"
+then
+	CFLAGS="$OLD_CFLAGS -Wpointer-arith"
+fi
+
 dnl **** Check for gcc strength-reduce bug ****
 
 if test "x${GCC}" = "xyes"
 then
-  CFLAGS="$CFLAGS -Wall -Wpointer-arith"
+  CFLAGS="$CFLAGS -Wall"
   AC_CACHE_CHECK( [for gcc strength-reduce bug], ac_cv_c_gcc_strength_bug,
                   AC_TRY_RUN([
 int	L[[4]] = {0,1,2,3};