perf tools: Display better error messages on missing packages

Check for libelf headers and glibc headers separately so that
the error message correctly identifies which package
installation is missing/needed.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: paulus@samba.org
Cc: a.p.zijlstra@chello.nl
Cc: efault@gmx.de
Cc: fweisbec@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <4ADBCCE8.3060300@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/Makefile

@@ -431,8 +431,12 @@ ifeq ($(uname_S),Darwin)
 	PTHREAD_LIBS =
 endif
 
+ifneq ($(shell sh -c "(echo '\#include <gnu/libc-version.h>'; echo 'int main(void) { const char * version = gnu_get_libc_version(); return (long)version; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	msg := $(error No gnu/libc-version.h found, please install glibc-dev[el]);
+endif
+
 ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
-	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
+	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel);
 endif
 
 ifdef NO_DEMANGLE