Add --target-glib command-line option, default to 2.12, based on patch by

Add --target-glib command-line option, default to 2.12, based on patch by

2008-08-10  Jürg Billeter  <j@bitron.ch>

	* vala/valacodecontext.vala:
	* gobject/valaccodeclassbinding.vala:
	* gobject/valaccodeinterfacebinding.vala:
	* gobject/valaclassregisterfunction.vala:
	* gobject/valainterfaceregisterfunction.vala:
	* gobject/valatyperegisterfunction.vala:
	* compiler/valacompiler.vala:

	Add --target-glib command-line option, default to 2.12,
	based on patch by Jared Moore, fixes bug 544990

svn path=/trunk/; revision=1746