tools lib: Adopt zalloc()/zfree() from tools/perf

Eroding a bit more the tools/perf/util/util.h hodpodge header.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-natazosyn9rwjka25tvcnyi0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/util.h

@@ -9,8 +9,6 @@
 #include <fcntl.h>
 #include <stdbool.h>
 #include <stddef.h>
-#include <stdlib.h>
-#include <stdarg.h>
 #include <linux/compiler.h>
 #include <sys/types.h>
 
@@ -18,13 +16,6 @@
 void usage(const char *err) __noreturn;
 void die(const char *err, ...) __noreturn __printf(1, 2);
 
-static inline void *zalloc(size_t size)
-{
-	return calloc(1, size);
-}
-
-#define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
-
 struct dirent;
 struct nsinfo;
 struct strlist;