diff --git a/Tools/Makefile.preamble b/Tools/Makefile.preamble
index 102875452..927b91965 100644
--- a/Tools/Makefile.preamble
+++ b/Tools/Makefile.preamble
@@ -45,7 +45,9 @@
 #ADDITIONAL_CFLAGS += 
 
 # Additional include directories the compiler should search
-ADDITIONAL_INCLUDE_DIRS += -I../src
+ADDITIONAL_INCLUDE_DIRS += -I../src \
+	-I../src/$(GNUSTEP_TARGET_CPU)/$(GNUSTEP_TARGET_OS)
+
 
 # Additional LDFLAGS to pass to the linker
 #ADDITIONAL_LDFLAGS +=