build: fix mismatch of MSVCRT in release mode

When building RelWithDebInfo, we would accidentally link against the debug
MSVCRT library rather than the release mode one resulting in memory corruptions.

Author: compnerd

cmake/modules/AddSwift.cmake

@@ -821,10 +821,10 @@ function(_add_swift_library_single target name)
     endif()
     list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;oldnames)
     # TODO(compnerd) handle /MT and /MTd
-    if("${CMAKE_BUILD_TYPE}" STREQUAL "RELEASE")
-      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;msvcrt)
-    else()
+    if(CMAKE_BUILD_TYPE MATCHES Debug)
       list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;msvcrtd)
+    else()
+      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS -Xfrontend;-autolink-library;-Xfrontend;msvcrt)
     endif()
   endif()