Fix global variables which call built-in functions.

When emitting a built-in function call, we need to honor the `fCPPMode`
state. Previously we were rewriting the call into a DSL call even in C++
mode.

We also now spell out Fract's complete namespace, to avoid a name
collision with MacTypes.h:

https://opensource.apple.com/source/CarbonHeaders/CarbonHeaders-18.1/MacTypes.h.auto.html
    typedef SInt32                          Fract;


Change-Id: I752b7816a64a9b2b2c79d92fe46cd774e1bab96a
Bug: skia:11854
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/401678
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
3 files changed