configure.ac: respect 'g' variants of libtool/libtoolize

BSD OS'es (OS X for me) provide GNU tools with prefixed 'g'. To find correct
versions of libtool/libtoolize on those systems search also for
glibtool/glibtoolize.

Signed-off-by: Andreas Bießmann <andreas@biessmann.de>
Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[yann.morin.1998@free.fr: search for the g-variant first]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <2f1530b54afcb6a00e1d.1395158786@andreas-mbp.er.biessmann.org>
Patchwork-Id: 331467

diff -durN binutils-2.20.1.orig/libiberty/Makefile.in binutils-2.20.1/libiberty/Makefile.in

--- binutils-2.20.1.orig/libiberty/Makefile.in	2009-08-23 21:03:58.000000000 +0200

+++ binutils-2.20.1/libiberty/Makefile.in	2010-08-17 19:32:19.000000000 +0200

@@ -227,6 +227,7 @@

 	  $(AR) $(AR_FLAGS) $(TARGETLIB) \

 	    $(REQUIRED_OFILES) $(EXTRA_OFILES) $(LIBOBJS); \

 	  $(RANLIB) $(TARGETLIB); \

+	  cp $(TARGETLIB) ../ ; \

 	  cd ..; \

 	else true; fi