gbuild: MSVC 2012 does not like /pdb for static libraries

Complains with warning LNK4044 and ignores it.

Change-Id: Ie91369339d121a652ce51e9229c3ef3b1c39d214
gbuild: TARGETGUI variable must be set on all LinkTargets

... otherwise it will get inherited from Executables to StaticLibraries
and then mt.exe will be unhappy and complain.

Change-Id: Ic9cc32ea3d0fb5d1fe91c1e9efa354fdf30c8264