diff --git a/lang/cem/libcc.ansi/misc/putenv.c b/lang/cem/libcc.ansi/misc/putenv.c
index 4c916e384..206ebaa94 100644
--- a/lang/cem/libcc.ansi/misc/putenv.c
+++ b/lang/cem/libcc.ansi/misc/putenv.c
@@ -46,6 +46,7 @@ putenv(char *name)
 				}
 			}
 		}
+		*r = '=';
 		v = environ;
 	}