gltrace: Make code 64-bit safe.

Currently, the trace API passes the pointers that need to be
patched up via 32 bit integers. Such code will not be 64 bit safe.
This patch sends all pointers in a separate array of pointers
for the fixup calls to read from.

Change-Id: If975333f11a6f6f9a74fba57de328affaed452a5