diff --git a/include/unixconf.h b/include/unixconf.h
index 236994bce..0d4fbce17 100644
--- a/include/unixconf.h
+++ b/include/unixconf.h
@@ -36,7 +36,9 @@
 #define NETWORK        /* if running on a networked system */
                        /* e.g. Suns sharing a playground through NFS */
 /* #define SUNOS4 */   /* SunOS 4.x */
-/* #define LINUX */    /* Another Unix clone */
+#ifdef __linux__
+#define LINUX    /* Another Unix clone */
+#endif
 /* #define CYGWIN32 */ /* Unix on Win32 -- use with case sensitive defines */
 /* #define GENIX */    /* Yet Another Unix Clone */
 /* #define HISX */     /* Bull Unix for XPS Machines */