From 5d2a1ad8d3e1749243829a51323b52f115031995 Mon Sep 17 00:00:00 2001
From: Edmond <resec0109@gmail.com>
Date: Tue, 16 May 2017 10:35:51 +0800
Subject: [PATCH] support using user-defined protoc via env var PROTOC

---
 configure.ac | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index f64a532..65558b8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,9 @@ LIBS="$LIBS $PROTOBUF_LIBS"
 
 m4_include([third_party/m4/ax_check_icu.m4])
 
-AC_CHECK_PROG([PROTOC], [protoc], [protoc])
+if test ! -n "$PROTOC"; then
+  AC_CHECK_PROG([PROTOC], [protoc], [protoc])
+fi
 AS_IF([test "x${PROTOC}" == "x"],
     [AC_MSG_ERROR([ProtoBuf compiler "protoc" not found. You can install them with "sudo apt-get install libprotobuf-c++ protobuf-compiler" ])])