https://bugs.gentoo.org/760633

From 41077f8901b642d36b63f94b0fc62377a07fc0b2 Mon Sep 17 00:00:00 2001
From: Adrian Ratiu <adrian.ratiu@collabora.com>
Date: Tue, 4 Jan 2022 03:51:10 +0200
Subject: [PATCH] Makefile: only run rpmspec if it exists

keyutils is built on many distros which do not use rpm like
Gentoo, ChromeOS or Arch. Older versions of bash silently
ignored the fact that rpmspec was missing, but newer bash
like v5.1 issue a new error:

/bin/sh: line 1: rpmspec: command not found

This happens every time the Makefile is parsed, including
for a simple "make" invocation or "make install" even if
a rpm package is not desired.

Arch Linux simply ignores this new error but Gentoo and
ChromeOS fail because portage actively monitors the build
log for errors like this. See bug report [1].

Fix this by calling rpmspec only if it exists.

[1] https://bugs.gentoo.org/760633

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
--- a/Makefile
+++ b/Makefile
@@ -285,7 +285,7 @@ SRCBALL	:= rpmbuild/SOURCES/$(TARBALL)
 ZSRCBALL := rpmbuild/SOURCES/$(ZTARBALL)
 
 BUILDID	:= .local
-rpmver0	:= $(shell rpmspec -q ./keyutils.spec --define "buildid $(BUILDID)")
+rpmver0	:= $(shell if which rpmspec >/dev/null 2>&1; then rpmspec -q ./keyutils.spec --define "buildid $(BUILDID)"; fi)
 rpmver1	:= $(word 1,$(rpmver0))
 rpmver2	:= $(subst ., ,$(rpmver1))
 rpmver3	:= $(lastword $(rpmver2))