diff --git a/Makefile.system b/Makefile.system
index ae6db40b0..af840f029 100644
--- a/Makefile.system
+++ b/Makefile.system
@@ -1170,6 +1170,8 @@ CCOMMON_OPT += -DF_INTERFACE_IBM
 FEXTRALIB += -lxlf90
 ifeq ($(C_COMPILER), GCC)
 FCOMMON_OPT += -qextname
+else ifeq ($(C_COMPILER), CLANG)
+FCOMMON_OPT += -qextname
 endif
 # FCOMMON_OPT	+= -qarch=440
 ifdef BINARY64