install a list of symbols generated by the PrintAsClang header

rdar://93504690

Author: QuietMisdreavus

lib/PrintAsClang/CMakeLists.txt

@@ -13,3 +13,19 @@ target_link_libraries(swiftPrintAsClang PRIVATE
   swiftIDE)
 
 set_swift_llvm_is_available(swiftPrintAsClang)
+
+# Add target to install the list of symbols added to compatibility headers
+set(symbols_file "${CMAKE_CURRENT_SOURCE_DIR}/compatibility_symbols")
+
+add_custom_target(swift-compatibility-symbols DEPENDS ${symbols_file})
+
+add_dependencies(swiftPrintAsClang swift-compatibility-symbols)
+
+swift_install_in_component(
+  FILES
+    ${symbols_file}
+  DESTINATION
+    "share/swift"
+  COMPONENT
+    compiler
+)

lib/PrintAsClang/PrintAsClang.cpp

@@ -53,6 +53,8 @@ static void emitObjCConditional(raw_ostream &out,
 static void writePrologue(raw_ostream &out, ASTContext &ctx,
                           StringRef macroGuard) {
 
+  // NOTE: If you add macros to this prologue, also add them to the `compatibility_symbols` file!
+
   out << "// Generated by "
       << version::getSwiftFullVersion(ctx.LangOpts.EffectiveLanguageVersion)
       << "\n"

lib/PrintAsClang/compatibility_symbols

@@ -0,0 +1,38 @@
+IBSegueAction
+OBJC_DESIGNATED_INITIALIZER
+SWIFT_AVAILABILITY
+SWIFT_CALL
+SWIFT_CLASS
+SWIFT_CLASS_EXTRA
+SWIFT_CLASS_NAMED
+SWIFT_CLASS_PROPERTY
+SWIFT_COMPILE_NAME
+SWIFT_CXX_INT_DEFINED
+SWIFT_DEPRECATED
+SWIFT_DEPRECATED_MSG
+SWIFT_DEPRECATED_OBJC
+SWIFT_ENUM
+SWIFT_ENUM_ATTR
+SWIFT_ENUM_EXTRA
+SWIFT_ENUM_NAMED
+SWIFT_EXTENSION
+SWIFT_EXTERN
+SWIFT_METATYPE
+SWIFT_METHOD_FAMILY
+SWIFT_NOESCAPE
+SWIFT_NOEXCEPT
+SWIFT_NORETURN
+SWIFT_PASTE
+SWIFT_PASTE_HELPER
+SWIFT_PROTOCOL
+SWIFT_PROTOCOL_EXTRA
+SWIFT_PROTOCOL_NAMED
+SWIFT_RELEASES_ARGUMENT
+SWIFT_RESILIENT_CLASS
+SWIFT_RESILIENT_CLASS_NAMED
+SWIFT_RUNTIME_NAME
+SWIFT_TYPEDEFS
+SWIFT_UNAVAILABLE
+SWIFT_UNAVAILABLE_MSG
+SWIFT_WARN_UNUSED_RESULT
+SWIFT_WEAK_IMPORT