diff --git a/dmd/mars.c b/dmd/mars.c
index 9f8fedf4..853637d0 100644
--- a/dmd/mars.c
+++ b/dmd/mars.c
@@ -319,6 +319,7 @@ int main(int argc, char *argv[])
     tt_os = "-pc-mingw32";
 #elif linux
     VersionCondition::addPredefinedGlobalIdent("linux");
+    VersionCondition::addPredefinedGlobalIdent("Unix");
     global.params.isLinux = 1;
     tt_os = "-pc-linux-gnu";
 #else