perf tools: Put common histogram functions in their own file

Move histogram related functions into their own files (hist.c and
hist.h) and make use of them in builtin-annotate.c and
builtin-report.c.

Signed-off-by: John Kacur <jkacur@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <alpine.LFD.2.00.0909281531180.8316@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 0a9e5ae..3a99a9f 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -340,6 +340,7 @@
 LIB_H += util/color.h
 LIB_H += util/values.h
 LIB_H += util/sort.h
+LIB_H += util/hist.h
 
 LIB_OBJS += util/abspath.o
 LIB_OBJS += util/alias.o
@@ -376,6 +377,7 @@
 LIB_OBJS += util/trace-event-info.o
 LIB_OBJS += util/svghelper.o
 LIB_OBJS += util/sort.o
+LIB_OBJS += util/hist.o
 
 BUILTIN_OBJS += builtin-annotate.o
 BUILTIN_OBJS += builtin-help.o