Index: libc/Makefile.toolchain
===================================================================
--- libc/Makefile.toolchain	(revision d3cd9774e03c0d86ad7ba5d0b6c3d4d76f8d6fc0)
+++ libc/Makefile.toolchain	(revision 09087d23b91c8b197f3dea51ee0b4dd0a6b2a18b)
@@ -28,5 +28,5 @@
 
 DEFS = -DARCH=$(ARCH)
-CFLAGS = -fno-builtin -Werror-implicit-function-declaration -Wmissing-prototypes -O3 -nostdlib -nostdinc -I$(LIBC_PREFIX)/include
+CFLAGS = -fno-builtin -Wall -Werror-implicit-function-declaration -Wmissing-prototypes -O3 -nostdlib -nostdinc -I$(LIBC_PREFIX)/include
 LFLAGS = -M -N $(SOFTINT_PREFIX)/libsoftint.a
 AFLAGS =