diff --git a/lib/sparc/descr b/lib/sparc/descr
index ee427f98d..fd95cb06e 100644
--- a/lib/sparc/descr
+++ b/lib/sparc/descr
@@ -9,7 +9,7 @@ var NAME=sparc
 var M=sparc
 var LIB=lib/{M}/tail_
 var RT=lib/{M}/head_
-var CPP_F=-D__unix -D__sparc -D__BSD4_2
+var CPP_F=-D__unix -D__sparc -D__BSD4_2 -D__sun
 var CC_ALIGN=-VS4 -S9
 var C_LIB={EM}/{LIB}cc.1s {EM}/{LIB}cc.2g
 var OLD_C_LIB={C_LIB}