set -C
while : ; do i=$(($i+1))
tmpc="./conf$$-$PPID-$i.c"
-2>/dev/null > "$tmpc" && break
+2>|/dev/null > "$tmpc" && break
test "$i" -gt 50 && fail "$0: cannot create temporary file $tmpc"
done
set +C
fnmatch '-mtune=*|*\ -mtune=*' "$CFLAGS" || tryldflag CFLAGS_AUTO -mtune=generic
fi
+#
+# Even with -std=c99, gcc accepts some constructs which are constraint
+# violations. We want to treat these as errors regardless of whether
+# other purely stylistic warnings are enabled -- especially implicit
+# function declarations, which are a dangerous programming error.
+#
+tryflag CFLAGS_AUTO -Werror=implicit-function-declaration
+tryflag CFLAGS_AUTO -Werror=implicit-int
+tryflag CFLAGS_AUTO -Werror=pointer-sign
+tryflag CFLAGS_AUTO -Werror=pointer-arith
+
if test "x$warnings" = xyes ; then
tryflag CFLAGS_AUTO -Wall
-tryflag CFLAGS_AUTO -Wpointer-arith
tryflag CFLAGS_AUTO -Wcast-align
tryflag CFLAGS_AUTO -Wno-parentheses
tryflag CFLAGS_AUTO -Wno-uninitialized