diff --git a/package/flex/flex.mk b/package/flex/flex.mk
index b78269952e..0196624e9a 100644
--- a/package/flex/flex.mk
+++ b/package/flex/flex.mk
@@ -10,7 +10,8 @@ FLEX_INSTALL_STAGING = YES
 FLEX_LICENSE = FLEX
 FLEX_LICENSE_FILES = COPYING
 FLEX_DEPENDENCIES = $(TARGET_NLS_DEPENDENCIES) host-m4
-FLEX_CONF_ENV = ac_cv_path_M4=/usr/bin/m4
+FLEX_CONF_ENV = ac_cv_path_M4=/usr/bin/m4 \
+	ac_cv_func_reallocarray=no
 HOST_FLEX_DEPENDENCIES = host-m4
 
 define FLEX_DISABLE_PROGRAM