diff --git a/packages/devel/flex/package.mk b/packages/devel/flex/package.mk
index 9d910337bc..36d6b62b62 100644
--- a/packages/devel/flex/package.mk
+++ b/packages/devel/flex/package.mk
@@ -15,6 +15,9 @@ PKG_TOOLCHAIN="autotools"
 
 PKG_CONFIGURE_OPTS_HOST="--enable-static --disable-shared --disable-rpath --with-gnu-ld"
 
+PKG_CONFIGURE_OPTS_TARGET="ac_cv_func_realloc_0_nonnull=yes \
+                           ac_cv_func_malloc_0_nonnull=yes"
+
 post_makeinstall_host() {
   cat > $TOOLCHAIN/bin/lex << "EOF"
 #!/bin/sh