Mesa (master): configure.ac: Check for grep with AC_PROG_GREP

[Matt Turner]

Module: Mesa
Branch: master
Commit: 00979402230e659fff57dec612f60987665157fa
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=00979402230e659fff57dec612f60987665157fa

Author: Matt Turner <mattst88 at gmail.com>
Date:   Wed May  9 16:32:12 2018 -0700

configure.ac: Check for grep with AC_PROG_GREP

Perhaps with a new version of autoconf, I began seeing:

| checking the name lister (/usr/bin/nm -B) interface... ./configure: line 6973: External.*some_variable: command not found
| BSD nm

This is because AC_PROG_NM expands to

	...
	if $GREP 'External.*some_variable' conftest.out > /dev/null; then
	    lt_cv_nm_interface="MS dumpbin"
	fi
	...

I'm not sure if it's a bug in AC_PROG_NM that it doesn't call
AC_PROG_GREP, but it's easy enough for us to do it.

---

 configure.ac | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure.ac b/configure.ac
index c0fbfe9413..4bb89607e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,6 +119,7 @@ dnl other CC/CXX flags related help
 AC_ARG_VAR([CXX11_CXXFLAGS], [Compiler flag to enable C++11 support (only needed if not
                               enabled by default and different  from -std=c++11)])
 AM_PROG_CC_C_O
+AC_PROG_GREP
 AC_PROG_NM
 AM_PROG_AS
 AX_CHECK_GNU_MAKE