GIR writer: Generate constant c:identifier and value
GIR writer: Generate constant c:identifier and value

Signed-off-by: Didier 'Ptitjes <9b75d9bd0301369bd978ce18252ab1844af4cc4b@free.fr>

tjol/vala-tjol,jessevdk/vala,kamanashisroy/aroop,spidermonkdust/vala,frida/vala,GNOME/vala,GNOME/vala,severinh/vala,playya/vala,kamanashisroy/aroop,playya/vala,themiwi/vala,lovebug356/vala,kamanashisroy/aroop,jessevdk/vala,Distrotech/vala,rvu95/vala,spidermonkdust/vala,GNOME/vala,Jc2k/vala,severinh/vala,themiwi/vala,lovebug356/vala,rvu95/vala,GNOME/vala,tjol/vala-tjol,phako/vala,frida/vala,rvu95/vala,severinh/vala,frida/vala,Jc2k/vala,Distrotech/vala,flobrosch/vala-fixes,playya/vala,frida/vala,flobrosch/vala-fixes,xdave/pvala,themiwi/vala,jessevdk/vala,flobrosch/vala-fixes,frida/vala,spidermonkdust/vala,Distrotech/vala,tjol/vala-tjol,phako/vala