[libc] Clean up Windows macros

[caitlyncano]

Summary

This clean-up removes checks for _WIN64, as the _WIN32 macro returns 1
whenever the compilation targe is 32- or 64-bit ARM, as well as x86 and x64
(see Windows pre-defined macro documentation
https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros).

[aeubanks]

not just ARM but also x86/x64 (which is what we're working with)

maybe a reference to https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros in the description would be good

libc/utils/UnitTest/PlatformDefs.h

12

extra parentheses

[caitlyncano]

[libc] Remove extra parentheses and reference documentation

[aeubanks]

lg after updating the description

libc/utils/FPUtil/PlatformDefs.h

 //===-- Platform specific macro definitions ---------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIBC_UTILS_FPUTIL_PLATFORM_DEFS_H
 #define LLVM_LIBC_UTILS_FPUTIL_PLATFORM_DEFS_H
 
 #if defined(__x86_64__) || defined(__i386__)
 #define X87_FPU
 #endif
 
-#if defined(_WIN32) || defined(_WIN64)
+#if defined(_WIN32)
 #define LONG_DOUBLE_IS_DOUBLE
 #endif
 
 #if !defined(LONG_DOUBLE_IS_DOUBLE) && defined(X87_FPU)
 #define SPECIAL_X86_LONG_DOUBLE
 #endif
 
 #endif // LLVM_LIBC_UTILS_FPUTIL_PLATFORM_DEFS_H

libc/utils/FPUtil/TestHelpers.cpp

 
 template void describeValue<float>(const char *, float,
                                    testutils::StreamWrapper &);
 template void describeValue<double>(const char *, double,
                                     testutils::StreamWrapper &);
 template void describeValue<long double>(const char *, long double,
                                          testutils::StreamWrapper &);
 
-#if defined(_WIN32) || defined(_WIN64)
+#if defined(_WIN32)
 #define sigjmp_buf jmp_buf
 #define sigsetjmp(buf, save) setjmp(buf)
 #define siglongjmp(buf, val) longjmp(buf, val)
 #endif
 
 static thread_local sigjmp_buf jumpBuffer;
 static thread_local bool caughtExcept;
 

libc/utils/UnitTest/PlatformDefs.h

 //===-- Platform specific defines for the unittest library ------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIBC_UTILS_UNITTEST_PLATFORMDEFS_H
 #define LLVM_LIBC_UTILS_UNITTEST_PLATFORMDEFS_H
 
-#if !(defined(_WIN32) || defined(_WIN64))
+#if !defined(_WIN32)
 #define ENABLE_SUBPROCESS_TESTS
 #endif
 
 #endif // LLVM_LIBC_UTILS_UNITTEST_PLATFORMDEFS_H