All of the _Builtin_stdarg and _Builtin_stddef submodules need to be
allowed from [no_undeclared_includes] modules. Split the builtin headers
tests out from the compiler_builtins test so that the testing modules
can be modified without affecting the other many tests that use
Inputs/System/usr/include.
Make top level modules for all the C standard library headers.
The `__stddef` implementation headers need header guards now that they're all modular. stdarg.h and stddef.h will be textual headers in the builtin modules, and so need to be repeatedly included in both the system and builtin module case. Define their header guards for consistency, but ignore them when building with modules.
`__stddef_null.h` needs to ignore its header guard when modules aren't being used to fulfill its redefinition obligation.
`__stddef_nullptr_t.h` needs to add a guard for C23 so that `_Builtin_stddef` can compile in C17 and earlier modes. `_Builtin_stddef.nullptr_t` can't require C23 because it also needs to be usable from C++.
Reviewed By: Bigcheese
Differential Revision: https://reviews.llvm.org/D159064
into using non-absolute system includes (<foo>)...
... and introduce another hack that is simultaneously more heineous
and more effective. We whitelist Clang-supplied headers that augment
or override system headers (such as float.h, stdarg.h, and
tgmath.h). For these headers, Clang does not provide a module
mapping. Instead, a system-supplied module map can refer to these
headers in a system module, and Clang will look both in its own
include directory and wherever the system-supplied module map
suggests, then adds either or both headers. The end result is that
Clang-supplied headers get merged into the system-supplied module for
the C standard library.
As a drive-by, fix up a few dependencies in the _Builtin_instrinsics
module.
llvm-svn: 149611
