[poppler] configure.ac

[Albert Astals Cid]

Rebased ref, commits from common ancestor:
commit f0feeed3513899558c59b65f798f294212309486
Author: Matthias Kilian <kili at outback.escape.de>
Date:   Mon Aug 1 22:50:44 2016 +0200

    Work with non gnu grep

diff --git a/configure.ac b/configure.ac
index f008e25..aa6c166 100644
--- a/configure.ac
+++ b/configure.ac
@@ -779,13 +779,13 @@ if test x$enable_poppler_qt5 = xyes; then
     AC_CHECK_TOOL(MOCQT52, moc-qt5)
     AC_MSG_CHECKING([for Qt5 moc-qt5])
     mocversion=`$MOCQT52 -v 2>&1`
-    mocversiongrep=`echo $mocversion | grep "Qt 5\|moc-qt5 5\|moc 5"`
+    mocversiongrep=`echo $mocversion | grep -E "Qt 5|moc-qt5 5|moc 5"`
     if test x"$mocversiongrep" != x"$mocversion"; then
       AC_CHECK_TOOL(QTCHOOSER, qtchooser)
       AC_MSG_CHECKING([for qtchooser])
       qt5tooldir=`QT_SELECT=qt5 qtchooser -print-env | grep QTTOOLDIR | cut -d '=' -f 2 | cut -d \" -f 2`
       mocversion=`$qt5tooldir/moc -v 2>&1`
-      mocversiongrep=`echo $mocversion | grep "Qt 5\|moc 5"`
+      mocversiongrep=`echo $mocversion | grep -E "Qt 5|moc 5"`
       if test x"$mocversiongrep" != x"$mocversion"; then
         # no valid moc found
         enable_poppler_qt5=no;