Currently, the playground transform requires the use of dollar-identifiers as the functions are prefixed with "$builtin".
This commit removes that requirement by replacing "$builtin" with "__builtin".
This aligns with the PC macro.
This addresses <rdar://problem/36031860>.
This converts the instances of the pattern for which we have a proper
substitution in lit. This will make it easier to replace it
appropriately with Windows equivalents.
As with the playground transform, defer statements were not supported in the PC macro.
This commit addresses that oversight.
This partially addresses <rdar://problem/29007242>.
Based off the PlaygroundTransform, this new ASTWalker leaves calls to __builtin_pc_before and __builtin_pc_after before and after a user would expect a program counter to enter a range of source code.
