diff --git a/configure.ac b/configure.ac
index 006c8fa5..f3e113ec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -101,7 +101,10 @@ AS_CASE(["$host"],
     [*-apple-darwin*],               [WM_OSDEP="darwin"],
     [*-*-solaris*],                  [WM_OSDEP="stub"],  dnl  solaris.c when done
     [WM_OSDEP="stub"])
-AC_SUBST(WM_OSDEP)
+AM_CONDITIONAL([WM_OSDEP_LINUX],   [test "x$WM_OSDEP" = "xlinux"])
+AM_CONDITIONAL([WM_OSDEP_BSD],     [test "x$WM_OSDEP" = "xbsd"])
+AM_CONDITIONAL([WM_OSDEP_DARWIN],  [test "x$WM_OSDEP" = "xdarwin"])
+AM_CONDITIONAL([WM_OSDEP_GENERIC], [test "x$WM_OSDEP" = "xstub"])
 
 
 dnl the prefix
diff --git a/src/Makefile.am b/src/Makefile.am
index f67e1cfb..2d1bd2bb 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -49,7 +49,6 @@ wmaker_SOURCES = 	\
 	menu.h \
 	misc.c \
 	misc.h \
-	osdep_@WM_OSDEP@.c \
 	monitor.c \
 	motif.c \
 	motif.h \
@@ -105,7 +104,18 @@ wmaker_SOURCES = 	\
 	workspace.c \
 	workspace.h
 
-EXTRA_wmaker_SOURCES = osdep_bsd.c osdep_darwin.c osdep_linux.c osdep_stub.c
+if WM_OSDEP_BSD
+wmaker_SOURCES += osdep_bsd.c
+endif
+if WM_OSDEP_DARWIN
+wmaker_SOURCES += osdep_darwin.c
+endif
+if WM_OSDEP_LINUX
+wmaker_SOURCES += osdep_linux.c
+endif
+if WM_OSDEP_GENERIC
+wmaker_SOURCES += osdep_stub.c
+endif
 
 AM_CFLAGS =