This reverts commit b9abc6139a and the
follow on fixes (7aae704 and 6fe1b47). It's changing the glapi/driver
ABI and causes a number of problems for debug/non-debug builds.
There's a useful feature buried in glapi to log all API calls to stderr.
Unfortunately it requires editing the code and then it's enabled
unconditionally for that build. This patch builds in API logging for
debug builds and makes it run-time switchable by setting MESA_DEBUG=dispatch.
