Merge pull request #21196 from apple/the-runtime-stands-alone-5

[5.0] build: always process `include`

Author: bob-wilson

CMakeLists.txt

@@ -912,8 +912,9 @@ endif()
 # https://bugs.swift.org/browse/SR-5975
 add_subdirectory(stdlib)
 
+add_subdirectory(include)
+
 if(SWIFT_INCLUDE_TOOLS)
-  add_subdirectory(include)
   add_subdirectory(lib)
 
   # Always include this after including stdlib/!