build system: do not rebuild entire tree if it is moved
diff --git a/Makefile.flags b/Makefile.flags
index 61bff4f..f27c601 100644
--- a/Makefile.flags
+++ b/Makefile.flags
@@ -11,7 +11,7 @@
CPPFLAGS += \
-Iinclude -Ilibbb \
- $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) -I$(srctree)/libbb \
+ $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include -I$(srctree)/libbb) \
-include include/autoconf.h \
-D_GNU_SOURCE -DNDEBUG \
$(if $(CONFIG_LFS),-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64) \