diff --git a/src/Makefile b/src/Makefile
index dfcf7a34..8aed1900 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -40,7 +40,7 @@ LIBS += -lucl -lz
 # you should set envvar UPX_LZMADIR to point to your unpacked lzma443.tar.bz2
 ifneq ($(wildcard $(UPX_LZMADIR)/C/7zip),)
 DEFS += -DWITH_LZMA
-INCLUDES += -I$(LZMADIR)
+INCLUDES += -I$(UPX_LZMADIR)
 endif
 
 upx_SOURCES := $(wildcard $(srcdir)/*.cpp)
diff --git a/src/conf.h b/src/conf.h
index 8953fbae..a5d13a89 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -144,12 +144,17 @@
 #  undef __unix
 #endif
 
-#if 1 && !defined(WITH_LZMA)
-#  define WITH_LZMA 1
-#endif
 #if !defined(WITH_UCL)
 #  define WITH_UCL 1
 #endif
+#if 0 && !defined(WITH_LZMA)
+#  define WITH_LZMA 1
+#endif
+#if defined(UPX_OFFICIAL_BUILD)
+#  if !defined(WITH_LZMA) || !defined(WITH_NRV) || !defined(WITH_UCL)
+#    error
+#  endif
+#endif
 #if defined(WITH_NRV)
 #  include <nrv/nrvconf.h>
 #endif