Fix go configuration and SWIG_GCC_VERSION

- in configure.ac: modify sed expression to only look at first line of
  gccgo --version, extract the last numeric token, and remove periods;
  this parses e.g. "gccgo (Debian 4.7.2-5) 4.7.2"
- in goruntime.swg: fix typo in __GNUC_PATCHLEVEL__ (SF Bug #1298)

CHANGES.current

@@ -8,6 +8,10 @@ Version 3.0.1 (in progress)
 2014-05-01: olly
 	    [PHP] The generated __isset() method now returns true for read-only properties.
 
+2014-04-24: kwwette
+            [Go] Fix go ./configure parsing of gccgo --version, and
+            goruntime.swg typo in __GNUC_PATCHLEVEL__ (SF Bug #1298)
+
 2014-04-24: kwwette
             Fix {python|perl5|ruby|tcl}/java examples