build: always report the status of building Differentiation

This moves the build configuration information into the block which
prints the full configuration details for the Swift runtime.  Simplify
the condition by merging the two blocks for building the standard
library and the `Differentiation` module.

Author: compnerd

CMakeLists.txt

@@ -877,6 +877,9 @@ if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_SDK_OVERLAY)
   message(STATUS "Building Swift runtime with:")
   message(STATUS "  Leak Detection Checker Entrypoints: ${SWIFT_RUNTIME_ENABLE_LEAK_CHECKER}")
   message(STATUS "")
+
+  message(STATUS "Differentiable Programming Support: ${SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING}")
+  message(STATUS "")
 else()
   message(STATUS "Not building Swift standard library, SDK overlays, and runtime")
   message(STATUS "")

stdlib/public/CMakeLists.txt

@@ -61,12 +61,10 @@ if(SWIFT_BUILD_STDLIB)
   add_subdirectory(stubs)
   add_subdirectory(core)
   add_subdirectory(SwiftOnoneSupport)
-endif()
 
-# Build differentiable programming support library only if enabled.
-if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING AND SWIFT_BUILD_STDLIB)
-  message(STATUS "Building Swift differentiable programming support library.")
-  add_subdirectory(Differentiation)
+  if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
+    add_subdirectory(Differentiation)
+  endif()
 endif()
 
 if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_REMOTE_MIRROR)