diff --git a/configure.in b/configure.in
index c77bb4b2..209c1979 100644
--- a/configure.in
+++ b/configure.in
@@ -406,8 +406,11 @@ case "$target" in
        AC_DEFINE(MACOSX, 1, [Compiling on Mac OS X])
        LIBS="$LIBS -framework AudioUnit"
        ;;
-    *-*-freebsd* | *-*-linux* | *-*-dragonfly* | *-*-netbsd* | *-*-openbsd*)
-       AC_DEFINE(LINUX, 1, [Compiling on GNU/Linux or *BSD])
+    *-*-linux*)
+       AC_DEFINE(LINUX, 1, [Compiling on GNU/Linux])
+       AC_DEFINE(C_DIRECTSERIAL, 1, [ Define to 1 if you want serial passthrough support (Win32, Posix and OS/2).])
+       ;;
+    *-*-freebsd* | *-*-dragonfly* | *-*-netbsd* | *-*-openbsd*)
        AC_DEFINE(C_DIRECTSERIAL, 1, [ Define to 1 if you want serial passthrough support (Win32, Posix and OS/2).])
        ;;
     *-*-os2-emx*)