diff --git a/Makefile.system b/Makefile.system
index 5a4af96988..ae6db40b0e 100644
--- a/Makefile.system
+++ b/Makefile.system
@@ -1167,6 +1167,10 @@ endif
 
 ifeq ($(F_COMPILER), IBM)
 CCOMMON_OPT += -DF_INTERFACE_IBM
+FEXTRALIB += -lxlf90
+ifeq ($(C_COMPILER), GCC)
+FCOMMON_OPT += -qextname
+endif
 # FCOMMON_OPT	+= -qarch=440
 ifdef BINARY64
 FCOMMON_OPT += -q64