Tweak gcc command like flags

ChangeLog

 2020-04-27  Niels Möller  <nisse@lysator.liu.se>
 
+	* configure.ac: Tweak gcc command line options. Delete checks for
+	older gcc versions. Add -Wno-sign-compare, since warnings for
+	signed/unsigned comparisons adds a lot of noise, in particular
+	when building mini-gmp.
+
 	* mini-gmp.c: Updated mini-gmp from the gmp repository, latest
 	change from 2020-04-20.
 	* mini-gmp.h: Likewise.

configure.ac

@@ -1006,18 +1006,7 @@ AC_SUBST(BENCH_LIBS)
 
 # Set these flags *last*, or else the test programs won't compile
 if test x$GCC = xyes ; then
-  # Using -ggdb3 makes (some versions of) Redhat's gcc-2.96 dump core
-  if $CC --version | grep '^2\.96$' 1>/dev/null 2>&1; then
-    true
-  else
-    CFLAGS="$CFLAGS -ggdb3"
-  fi
-  # FIXME: It would be better to actually test if this option works and/or is needed.
-  # Or perhaps use -funsigned-char.
-  if $CC --version | grep 'gcc.* 4\.' 1>/dev/null 2>&1; then
-    CFLAGS="$CFLAGS -Wno-pointer-sign"
-  fi
-  CFLAGS="$CFLAGS -Wall -W \
+  CFLAGS="$CFLAGS -ggdb3 -Wall -W -Wno-sign-compare \
   -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes \
   -Wpointer-arith -Wbad-function-cast -Wnested-externs"