From 39cb19303c9f9dbd0bdd67d266bfbbe076c6ebc5 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Sat, 23 May 2020 22:04:11 +0900
Subject: [PATCH] Search pkg-config with ac_tool_prefix [Bug #16909]

Should prefer a prefixed version over the bare pkg-config for
cross compiling.
---
 configure.ac | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 5993cf52dc..a33caa5367 100644
--- a/configure.ac
+++ b/configure.ac
@@ -406,8 +406,11 @@ AS_IF([test "$cross_compiling:$ac_cv_prog_DTRACE" = no: -a -n "$ac_tool_prefix"]
 AC_CHECK_PROGS(DOT, dot)
 AC_CHECK_PROGS(DOXYGEN, doxygen)
 
-AC_CHECK_PROG(PKG_CONFIG, pkg-config, [pkg-config], [], [],
-    [`"$as_dir/$ac_word$ac_exec_ext" --print-errors --version > /dev/null 2>&1 || echo "$as_dir/$ac_word$ac_exec_ext"`])
+for prog in ${ac_tool_prefix:+${ac_tool_prefix}pkg-config} pkg-config; do
+    AC_CHECK_PROG(PKG_CONFIG, $prog, [$prog], [], [],
+        [`"$as_dir/$ac_word$ac_exec_ext" --print-errors --version > /dev/null 2>&1 || echo "$as_dir/$ac_word$ac_exec_ext"`])
+    test -z "${PKG_CONFIG}" || break
+done
 
 # checks for UNIX variants that set C preprocessor variables
 AC_USE_SYSTEM_EXTENSIONS