When I did a compile of perf using a relative path for the output
directory, the build failed when it tried to compile libtraceevent. This
is because it continues to use the same relative path when the new
working directory is in a different path.

    SUBDIR ../lib/traceevent/
/bin/sh: line 0: cd: ../../../nobackup/perf/: No such file or directory
Makefile:74: *** output directory "../../../nobackup/perf/" does not exist.  Stop.
make: *** [../../../nobackup/perf///libtraceevent.a] Error 2

Make the path used an absolute path when building perf with O=.

Boris:

Teach Makefile to check whether the supplied O= directory exists and
bail out if not. Reportedly, kernel dudes are idiots and need to be
guarded so as not to shoot themselves in the foot when playing in the
sandbox.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120815163923.GD15989@aftab.osrc.amd.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Have building perf also build libtraceevent.a. Currently, perf does
not use the code within libtraceevent.a, but it soon will.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Use += instead of the bash syntax, as Sam Ravnborg suggests. Also, sort
the -W options alphabetically and (... keep them sorted).
Suggested-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: http://lkml.kernel.org/r/1334162178-17152-3-git-send-email-bp@amd64.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Put generic enough build settings which could be reused by other tools
into a common Makefile.include file.

This commit reintroduces QUIET_SUBDIR{0,1} (see a3d1ee10) which are
going to be used in the following patches.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: http://lkml.kernel.org/r/1334162178-17152-2-git-send-email-bp@amd64.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>