tools build: Add tools tree support for 'make -s'

When doing a kernel build with 'make -s', everything is silenced except
the objtool build.  That's because the tools tree support for silent
builds is some combination of missing and broken.

Three changes are needed to fix it:

- Makefile: propagate '-s' to the sub-make's MAKEFLAGS variable so the
  tools Makefiles can see it.

- tools/scripts/Makefile.include: fix the tools Makefiles' ability to
  recognize '-s'.  The MAKE_VERSION and MAKEFLAGS checks are copied from
  the top-level Makefile.  This silences the "DESCEND objtool" message.

- tools/build/Makefile.build: add support to the tools Build files for
  recognizing '-s'.  Again the MAKE_VERSION and MAKEFLAGS checks are
  copied from the top-level Makefile.  This silences all the object
  compile/link messages.

Reported-and-Tested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michal Marek <[email protected]>
Link: http://lkml.kernel.org/r/e8967562ef640c3ae9a76da4ae0f4e47df737c34.1484799200.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/build/Makefile.build

@@ -19,6 +19,16 @@ else
   Q=@
 endif
 
+ifneq ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
+ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
+  quiet=silent_
+endif
+else					# make-3.8x
+ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
+  quiet=silent_
+endif
+endif
+
 build-dir := $(srctree)/tools/build
 
 # Define $(fixdep) for dep-cmd function