diff --git a/lib/libgcc_s/Makefile b/lib/libgcc_s/Makefile
index 78b6515996f..62be480231d 100644
--- a/lib/libgcc_s/Makefile
+++ b/lib/libgcc_s/Makefile
@@ -14,6 +14,10 @@ VERSION_MAP=	${.CURDIR}/Version.map
 .include "../libcompiler_rt/Makefile.inc"
 .include "../libgcc_eh/Makefile.inc"
 
+# gcc has incompatible internal declarations for __divtc3 and __multc3, but has
+# no option to silence its warning, so make warnings non-fatal.
+NO_WERROR.gcc=
+
 LIBCSRCDIR=	${SRCTOP}/lib/libc
 LIBMSRCDIR=	${SRCTOP}/lib/msun/src
 CFLAGS+=	-I${LIBCSRCDIR}/include -I${LIBCSRCDIR}/${MACHINE_CPUARCH}