Add explicit check for EGREP in configure.ac

It is used in lib/Makefile.am and we were relying some autoconf macros
to define it as a side-effect. This is not the case anymore as of
autoconf 2.72.

diff --git a/configure.ac b/configure.ac
index 4be32fa9c0b8e79c88b018037b3397af1ad6f22f..c796b60f9d45d370a9e32f6a355587651a7cfdb9 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -122,6 +122,9 @@ AC_SUBST([HAVE_WCHAR_T])
 # Needed for Mingw-w64
 AC_TYPE_LONG_LONG_INT
 
+# egrep is used in lib/Makefile.am
+AC_PROG_EGREP
+
 ### We need iconv for unicode support (Qt frontend requires it too)
 LYX_USE_INCLUDED_ICONV