shader-effect: Zero out ShaderUniform
shader-effect: Zero out ShaderUniform

Do not use the compiler to zero the first field of the GValue member,
since it's apparently non-portable. As we're allocating memory anyway we
can let the slice allocator do the zero-ing for us.

Mentioned in: http://bugzilla.clutter-project.org/show_bug.cgi?id=2455

djdeath/clutter-android,djdeath/clutter-android,djdeath/clutter,djdeath/clutter-android,GNOME/clutter,djdeath/clutter,spatulasnout/clutter,dlespiau/clutter,collects/clutter,heysion/clutter-clone,collects/clutter,jigpu/clutter,spatulasnout/clutter,kerrickstaley/clutter-vala,kerrickstaley/clutter-vala,jigpu/clutter,djdeath/clutter,heysion/clutter-clone,djdeath/clutter,GNOME/clutter,ebassi/clutter,nobled/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,GNOME/clutter,heysion/clutter-clone,djdeath/clutter-android,dlespiau/clutter,ebassi/clutter,djdeath/clutter-android,dlespiau/clutter,nobled/clutter,heysion/clutter-clone,spatulasnout/clutter,jigpu/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,Distrotech/clutter,djdeath/clutter,kerrickstaley/clutter-vala,Distrotech/clutter,jigpu/clutter,Distrotech/clutter,heysion/clutter-clone,collects/clutter,Distrotech/clutter,ebassi/clutter,GNOME/clutter,djdeath/clutter-multithreaded,djdeath/clutter,ebassi/clutter,djdeath/clutter-multithreaded,jigpu/clutter,spatulasnout/clutter,collects/clutter,kerrickstaley/clutter-vala,collects/clutter,ebassi/clutter,jigpu/clutter,nobled/clutter,GNOME/clutter,spatulasnout/clutter