put -std=c99 in CFLAGS_NODIST

configure

@@ -6694,8 +6694,6 @@ then
 	    SCO_SV*) OPT="$OPT -m486 -DSCO5"
 	    ;;
         esac
-
-        OPT="$OPT -std=c99"
 	;;
 
     *)
@@ -6714,6 +6712,8 @@ UNIVERSAL_ARCH_FLAGS=
 # tweak BASECFLAGS based on compiler and platform
 case $GCC in
 yes)
+    CFLAGS_NODIST="$CFLAGS_NODIST -std=c99"
+
     # Python doesn't violate C99 aliasing rules, but older versions of
     # GCC produce warnings for legal Python code.  Enable
     # -fno-strict-aliasing on versions of GCC that support but produce

configure.ac

@@ -1458,8 +1458,6 @@ then
 	    SCO_SV*) OPT="$OPT -m486 -DSCO5"
 	    ;;
         esac
-
-        OPT="$OPT -std=c99"
 	;;
 
     *)
@@ -1478,6 +1476,8 @@ AC_SUBST(UNIVERSAL_ARCH_FLAGS)
 # tweak BASECFLAGS based on compiler and platform
 case $GCC in
 yes)
+    CFLAGS_NODIST="$CFLAGS_NODIST -std=c99"
+
     # Python doesn't violate C99 aliasing rules, but older versions of
     # GCC produce warnings for legal Python code.  Enable
     # -fno-strict-aliasing on versions of GCC that support but produce