diff --git a/configure b/configure
index 5831e1abb..21d56f387 100644
--- a/configure
+++ b/configure
@@ -7,7 +7,7 @@
 
 # CFLAGS and OPTIMIZE are different so you can add extra CFLAGS without
 # disabling default optimizations
-[ -z "$CFLAGS" ] && CFLAGS="-Wall -Wundef -Wno-char-subscripts -Wno-string-plus-int"
+[ -z "$CFLAGS" ] && CFLAGS="-Wall -Wundef -Wno-char-subscripts"
 # Required for our expected ABI. we're 8-bit clean thus "char" must be unsigned.
 CFLAGS="$CFLAGS -funsigned-char"
 [ -z "$OPTIMIZE" ] && OPTIMIZE="-Os -ffunction-sections -fdata-sections -fno-asynchronous-unwind-tables"
diff --git a/scripts/genconfig.sh b/scripts/genconfig.sh
index b8dc3c796..313c7c70e 100755
--- a/scripts/genconfig.sh
+++ b/scripts/genconfig.sh
@@ -7,12 +7,16 @@ mkdir -p generated
 
 source configure
 
+probecc()
+{
+  ${CROSS_COMPILE}${CC} $CFLAGS -xc -o /dev/null $1 -
+}
+
 # Probe for a single config symbol with a "compiles or not" test.
 # Symbol name is first argument, flags second, feed C file to stdin
 probesymbol()
 {
-  ${CROSS_COMPILE}${CC} $CFLAGS -xc -o /dev/null $2 - 2>/dev/null
-  [ $? -eq 0 ] && DEFAULT=y || DEFAULT=n
+  probecc $2 2>/dev/null && DEFAULT=y || DEFAULT=n
   rm a.out 2>/dev/null
   echo -e "config $1\n\tbool" || exit 1
   echo -e "\tdefault $DEFAULT\n" || exit 1
@@ -20,6 +24,13 @@ probesymbol()
 
 probeconfig()
 {
+  > generated/cflags
+  # llvm produces its own really stupid warnings about things that aren't wrong,
+  # and although you can turn the warning off, gcc reacts badly to command line
+  # arguments it doesn't understand. So probe.
+  [ -z "$(probecc -Wno-string-plus-int <<< \#warn warn 2>&1 | grep string-plus-int)" ] &&
+    echo -Wno-string-plus-int >> generated/cflags
+
   # Probe for container support on target
   probesymbol TOYBOX_CONTAINER << EOF
     #include <linux/sched.h>
diff --git a/scripts/make.sh b/scripts/make.sh
index 56fcc7e77..7ebe148df 100755
--- a/scripts/make.sh
+++ b/scripts/make.sh
@@ -62,6 +62,7 @@ GITHASH="$(git describe --tags --abbrev=12 2>/dev/null)"
 [ ! -z "$GITHASH" ] && GITHASH="-DTOYBOX_VERSION=\"$GITHASH\""
 TOYFILES="$(sed -n 's/^CONFIG_\([^=]*\)=.*/\1/p' "$KCONFIG_CONFIG" | xargs | tr ' [A-Z]' '|[a-z]')"
 TOYFILES="$(egrep -l "TOY[(]($TOYFILES)[ ,]" toys/*/*.c)"
+CFLAGS="$CFLAGS $(cat generated/cflags)"
 BUILD="$(echo ${CROSS_COMPILE}${CC} $CFLAGS -I . $OPTIMIZE $GITHASH)"
 FILES="$(echo lib/*.c main.c $TOYFILES)"