Update the default version of GCC used in the Ports Collection from

GCC 4.6.4 to GCC 4.7.3.  This entails updating the lang/gcc port as
well as changing the default in Mk/bsd.default-versions.mk.

Part II, Bump PORTREVISIONs.

PR:		182136
Supported by:	Christoph Moench-Tegeder <cmt@burggraben.net> (fixing many ports)
Tested by:	bdrewery (two -exp runs)

math/py-gnuplot/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	gnuplot
 PORTVERSION=	1.8
-PORTREVISION=	5
+PORTREVISION=	6
 CATEGORIES=	math python
 MASTER_SITES=	SF/${PORTNAME}-py/Gnuplot-py/${PORTVERSION}
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}