--- sbcl-2.4.1/contrib/asdf-module.mk.orig
+++ sbcl-2.4.1/contrib/asdf-module.mk
@@ -12,7 +12,7 @@
 ASD=$(DEST)/$(SYSTEM).asd
 
 ifeq (SunOS,$(UNAME))
-  EXTRA_CFLAGS+=-D_XOPEN_SOURCE=500 -D__EXTENSIONS__
+  EXTRA_CFLAGS+=-D_XOPEN_SOURCE=600 -D__EXTENSIONS__
   PATH:=/usr/xpg4/bin:${PATH}
 endif
 ifeq (CYGWIN,$(findstring CYGWIN,$(UNAME)))