Merge pull request #3219 from compnerd/library-optimization

build: improve static library generation

Author: gribozavr

CMakeLists.txt

@@ -307,6 +307,19 @@ option(SWIFT_BUILD_SOURCEKIT
     "Build SourceKit"
     ${SWIFT_BUILD_SOURCEKIT_default})
 
+#
+# Assume a new enough ar to generate the index at construction time.  This avois
+# having to invoke ranlib as a secondary command.
+#
+
+set(CMAKE_C_ARCHIVE_CREATE "<CMAKE_AR> crs <TARGET> <LINK_FLAGS> <OBJECTS>")
+set(CMAKE_C_ARCHIVE_APPEND "<CMAKE_AR> qs <TARGET> <LINK_FLAGS> <OBJECTS>")
+set(CMAKE_C_ARCHIVE_FINISH "")
+
+set(CMAKE_CXX_ARCHIVE_CREATE "<CMAKE_AR> crs <TARGET> <LINK_FLAGS> <OBJECTS>")
+set(CMAKE_CXX_ARCHIVE_APPEND "<CMAKE_AR> qs <TARGET> <LINK_FLAGS> <OBJECTS>")
+set(CMAKE_CXX_ARCHIVE_FINISH "")
+
 #
 # Include CMake modules
 #