--- a/src/ccache.c
+++ b/src/ccache.c
@@ -2277,6 +2277,7 @@ calculate_object_hash(struct args *args,
"CPLUS_INCLUDE_PATH",
"OBJC_INCLUDE_PATH",
"OBJCPLUS_INCLUDE_PATH", // clang
+ "GCC_HONOUR_COPTS",
NULL
};
for (const char **p = envvars; *p; ++p) {
