build: collect the build artifacts in a central location

This structures the build for Foundation similar to LLVM and most of the
other libraries.  Having a regular structure makes it easier to find the
artifacts and makes it easier to automate builds.

Author: compnerd

CMakeLists.txt

@@ -27,6 +27,16 @@ if(CMAKE_VERSION VERSION_LESS 3.16.0)
   set(CMAKE_LINK_LIBRARY_FLAG "-l")
 endif()
 
+if(CMAKE_VERSION VERSION_LESS 3.16 AND CMAKE_SYSTEM_NAME STREQUAL Windows)
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+else()
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+endif()
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+set(CMAKE_Swift_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/swift)
+
 option(BUILD_SHARED_LIBS "build shared libraries" ON)
 option(NS_CURL_ASSUME_FEATURES_MISSING "Assume that optional libcurl features are missing rather than test the library's version, for build debugging" NO)