[PATCH] kbuild: fix-rR-is-now-default

`make -d help | grep Makefile` shows patterns, where make tries to rebuild
included and top makefiles.

While `make -rR is now default' commit should fix this, actually, it was just
a little janitorial.

This fix is aimed to complete cancelling implicit rules.

Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Oleg Verych <olecom@flower.upol.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Makefile

@@ -10,8 +10,11 @@ NAME=Avast! A bilge rat!
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
 
-# Do not print "Entering directory ..."
-MAKEFLAGS += --no-print-directory
+# Do not:
+# o  use make's built-in rules and variables
+#    (this increases performance and avoid hard-to-debug behavour);
+# o  print "Entering directory ...";
+MAKEFLAGS += -rR --no-print-directory
 
 # We are using a recursive build, so we need to do a little thinking
 # to get the ordering right.
@@ -271,12 +274,8 @@ export quiet Q KBUILD_VERBOSE
 # Look for make include files relative to root of kernel src
 MAKEFLAGS += --include-dir=$(srctree)
 
-# We need some generic definitions
-include  $(srctree)/scripts/Kbuild.include
-
-# Do not use make's built-in rules and variables
-# This increases performance and avoid hard-to-debug behavour
-MAKEFLAGS += -rR
+# We need some generic definitions.
+include $(srctree)/scripts/Kbuild.include
 
 # Make variables (CC, etc...)
 
@@ -1484,6 +1483,8 @@ endif	# skip-makefile
 PHONY += FORCE
 FORCE:
 
+# Cancel implicit rules on top Makefile, `-rR' will apply to sub-makes.
+Makefile: ;
 
 # Declare the contents of the .PHONY variable as phony.  We keep that
 # information in a variable se we can use it in if_changed and friends.