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/include/linux/zalloc.h

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: LGPL-2.1
+#ifndef __TOOLS_LINUX_ZALLOC_H
+#define __TOOLS_LINUX_ZALLOC_H
+
+#include <stddef.h>
+
+void *zalloc(size_t size);
+void __zfree(void **ptr);
+
+#define zfree(ptr) __zfree((void **)(ptr))
+
+#endif // __TOOLS_LINUX_ZALLOC_H