Set LTGC for libraries to avoid the warning
Set LTGC for libraries to avoid the warning

This is to get rid of these messages:
"""
[2258/2395] LIB obj\syzygy\instrument\instrument_lib.lib
instrument_lib.thunk_import_references_transform.obj : MSIL .netmodule or module
 compiled with /GL found; restarting link with /LTCG; add /LTCG to the link comm
and line to improve linker performance
"""

BUG=

Review URL: https://codereview.chromium.org/1748903002

google/syzygy,Eloston/syzygy,Eloston/syzygy,google/syzygy,google/syzygy,google/syzygy