build system: remove some unnecessary rebuilds

diff --git a/applets/Kbuild b/applets/Kbuild
index 2969e79228f9860a36f7e27dc905e61086e84f6d..8aafe78fb3020d273fbe61df5ab64516b08e3701 100644 (file)
--- a/applets/Kbuild
+++ b/applets/Kbuild
@@ -13,18 +13,21 @@ hostprogs-y += usage applet_tables
 always:= $(hostprogs-y)
 
 # Generated files need additional love
+# NB: __srctree is either empty or "srctree/"
+# using it instead of srctree decreases amount of rebuilds
+# if tree is merely renamed/copied
 
-HOSTCFLAGS_usage.o = -I$(srctree)/include
+HOSTCFLAGS_usage.o = -I$(__srctree)include
 
 applets/applets.o: include/usage_compressed.h include/applet_tables.h
 
-applets/usage:         .config $(srctree)/applets/usage_compressed
+applets/usage:         .config $(__srctree)applets/usage_compressed
 applets/applet_tables: .config
 
 quiet_cmd_gen_usage_compressed = GEN     include/usage_compressed.h
-      cmd_gen_usage_compressed = $(srctree)/applets/usage_compressed include/usage_compressed.h applets
+      cmd_gen_usage_compressed = $(__srctree)applets/usage_compressed include/usage_compressed.h applets
 
-include/usage_compressed.h: applets/usage $(srctree)/applets/usage_compressed
+include/usage_compressed.h: applets/usage $(__srctree)applets/usage_compressed
        $(call cmd,gen_usage_compressed)
 
 quiet_cmd_gen_applet_tables = GEN     include/applet_tables.h