perf tools: Print warning when HAVE_DEBUGINFOD_SUPPORT is not set and user tries to use debuginfod support

When one requests debuginfod, either via --debuginfod option, or with a
perf-config value, complain when perf is not built with it.

Signed-off-by: Martin Liška <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/util.c

···
 		setenv("DEBUGINFOD_URLS", di->urls, 1);
 
 	pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
+
+#ifndef HAVE_DEBUGINFOD_SUPPORT
+	if (di->set)
+		pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
+#endif
 }
 
 /*