diff --git a/src/Makedefs.upx b/src/Makedefs.upx
index 96bcd551..75f6eb42 100644
--- a/src/Makedefs.upx
+++ b/src/Makedefs.upx
@@ -9,8 +9,9 @@ SHELL = /bin/sh
 .SUFFIXES: .a .c .cpp .exe .lib .o .obj .rc .res .ttp
 
 
+ifeq ($(srcdir),)
 srcdir = .
-top_srcdir = ..
+endif
 
 VPATH = $(srcdir)
 
diff --git a/src/Makefile b/src/Makefile
index 8d2f4b68..d9bf7fc2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -30,6 +30,9 @@ endif
 
 DEBUG = 0
 
+srcdir = .
+top_srcdir = ..
+
 
 ##### You should not have to change anything below this line. #####
 
diff --git a/src/stub/Makefile b/src/stub/Makefile
index 2968395b..1cc2e8cf 100644
--- a/src/stub/Makefile
+++ b/src/stub/Makefile
@@ -17,8 +17,8 @@ endif
 
 SHELL = /bin/sh
 
-top_srcdir = ../..
 srcdir = .
+top_srcdir = ../..
 
 
 # These are the files we want to create.