replace cmake rule with macro

Author: uzairnawaz

libc/src/__support/CMakeLists.txt

@@ -393,7 +393,7 @@ add_subdirectory(time)
 
 # Requires access to uchar header which is not on macos
 # Therefore, cannot currently build this on macos in overlay mode
-if(NOT (LIBC_TARGET_OS_IS_DARWIN OR LIBC_TARGET_OS_IS_WINDOWS))
+if(NOT (LIBC_TARGET_OS_IS_DARWIN))
   add_subdirectory(wchar)
 endif()
 

libc/test/src/__support/CMakeLists.txt

@@ -277,6 +277,6 @@ add_subdirectory(time)
 add_subdirectory(threads)
 # Requires access to uchar header which is not on MacOS
 # Cannot currently build this on MacOS in overlay mode
-if(NOT (LIBC_TARGET_OS_IS_DARWIN OR LIBC_TARGET_OS_IS_WINDOWS))
+if(NOT (LIBC_TARGET_OS_IS_DARWIN))
   add_subdirectory(wchar)
 endif()

libc/test/src/__support/wchar/string_converter_test.cpp

@@ -6,6 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO: add support for 16-bit widechars to StringConverter to remove this
+// macro
+#ifndef LIBC_TARGET_OS_IS_WINDOWS
+
 #include "hdr/errno_macros.h"
 #include "hdr/types/char32_t.h"
 #include "hdr/types/char8_t.h"
@@ -352,3 +356,5 @@ TEST(LlvmLibcStringConverterTest, DestLimitUTF32To8) {
   ASSERT_FALSE(res.has_value());
   ASSERT_EQ(static_cast<int>(sc.getSourceIndex()), 1);
 }
+
+#endif