Provides a new fallback for Process arguments for those instances where we do
not own main (e.g. Frameworks, Objective-C owns main.m or main.c, etc.). This
includes a number of platform-specific specializations of argument grabbing
logic and a new thread-safe interface to Process.unsafeArgv.
main() | _NSGetArgc/_NSGetArgv | /proc/self/cmdline | __argc/__argv
--------|--------------------------|------------------------|---------------
Scripts | OS X, iOS, tvOS, watchOS | Linux, FreeBSD, Cygwin | Windows
For interpreted Swift where we must filter out the arguments we now do so by
loading the standard library and calling into new SPI to override the arguments
that would have been grabbed by the runtime. This implementation completely
subsumes the use of the entry point '_stdlib_didEnterMain' and it will be
removed in a future commit.
Correct format:
```
//===--- Name of file - Description ----------------------------*- Lang -*-===//
```
Notes:
* Comment line should be exactly 80 chars.
* Padding: Pad with dashes after "Description" to reach 80 chars.
* "Name of file", "Description" and "Lang" are all optional.
* In case of missing "Lang": drop the "-*-" markers.
* In case of missing space: drop one, two or three dashes before "Name of file".
No intended functionality change, although this may make it easier to
get the REPL up and running on Linux. This is still useful for compiler
hackers even if it's not an end-user feature.
Swift SVN r31502
