[Headers][Modules] Make separate headers for the stdarg.h and stddef.h pieces so that they can be modularized
stdarg.h and stddef.h have to be textual headers in their upcoming modules to support their `__needs_xxx` macros. That means that they won't get precompiled into their modules' pcm, and instead their declarations will go into every other pcm that uses them. For now that's ok since the type merger can handle the declarations in these headers, but it's suboptimal at best. Make separate headers for all of the pieces so that they can be properly modularized.
Reviewed By: aaron.ballman, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D158709
GitOrigin-RevId: 680da4b5d7ec05a1e6656f2a7603a7b843268bab
Change-Id: I669371852f608ade447344e527aa39c212c0b383
1 file changed
