[clang] [Clang] Define `__WCHAR_MIN__` and related macros (PR #208135)

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github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 55692 tests passed
* 1375 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.Preprocessor/stdint.c</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\23\include -nostdsysteminc -E -ffreestanding -triple=arm-none-none C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe -check-prefix ARM C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\23\include' -nostdsysteminc -E -ffreestanding -triple=arm-none-none 'C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c'
# note: command had no output on stdout or stderr
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' -check-prefix ARM 'C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c:88:8: error: ARM: expected string not found in input
# | // ARM:SIG_ATOMIC_MIN_ (-2147483647 -1)
# |        ^
# | <stdin>:126:37: note: scanning from here
# | UINTMAX_MAX_ 18446744073709551615ULL
# |                                     ^
# | <stdin>:128:1: note: possible intended match here
# | SIG_ATOMIC_MIN_ (-2147483647 - 1)
# | ^
# | 
# | Input file: <stdin>
# | Check file: C:\_work\llvm-project\llvm-project\clang\test\Preprocessor\stdint.c
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |           121: PTRDIFF_MAX_ 2147483647 
# |           122: SIZE_MAX_ 4294967295U 
# |           123:  
# |           124: INTMAX_MIN_ (-9223372036854775807LL -1) 
# |           125: INTMAX_MAX_ 9223372036854775807LL 
# |           126: UINTMAX_MAX_ 18446744073709551615ULL 
# | check:88'0                                        {   search range start (exclusive)
# | check:88'1                                            error: no match found in search range
# |           127:  
# |           128: SIG_ATOMIC_MIN_ (-2147483647 - 1) 
# | check:88'2     ?                                   possible intended match
# |           129: SIG_ATOMIC_MAX_ 2147483647 
# |           130: WINT_MIN_ (-2147483647 - 1) 
# |           131: WINT_MAX_ 2147483647 
# |           132:  
# |           133: WCHAR_MAX_ 4294967295U 
# |             .
# |             .
# |             .
# |           141: UINT32_C_(0) 0U 
# |           142: INT64_C_(0) 0LL 
# |           143: UINT64_C_(0) 0ULL 
# |           144:  
# |           145: INTMAX_C_(0) 0LL 
# |           146: UINTMAX_C_(0) 0ULL 
# | check:88'3                        } search range end (exclusive)
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/208135