Use C++-11 for print/texlive/base

Hi,

the pending update of print/poppler will require the use of a C++-11
capable compiler, so set COMPILER=gcc.

Builds fine for me on amd64 (still with gcc as the default compiler
in base). Something in this port seems to need ${LIBCXX}, and setting
COMPILER=gcc appends ${LIBECXX}, so we now have both in WANTLIB. I
hope that's ok (texlive_base mostly contains binaries and only a
few libraries, so let's hope that nothing uses both ${LIBCXX} and
${LIBECXX}).

ok?

Ciao,
Kili

Index: Makefile
===================================================================
RCS file: /cvs/ports/print/texlive/base/Makefile,v
retrieving revision 1.88
diff -u -p -r1.88 Makefile
--- Makefile 21 May 2017 11:57:45 -0000 1.88
+++ Makefile 26 Jun 2017 18:56:15 -0000
@@ -7,6 +7,8 @@ DISTNAME = texlive-${DIST_V}b-source
PKGNAME = texlive_base-${V}
WRKDIST = ${WRKDIR}/texlive-${DIST_V}-source

+REVISION = 0
+
DISTFILES = ${DISTNAME}${EXTRACT_SUFX} \
texlive-${DIST_V}-extra${EXTRACT_SUFX}

@@ -43,6 +45,9 @@ LIB_DEPENDS = converters/libiconv \
graphics/potrace

MODULES = textproc/intltool perl
+
+# c++-11 required for poppler
+COMPILER = gcc

# Never set SEPARATE_BUILD
CONFIGURE_STYLE = gnu