Enabling Swift support is normally intended for building an overlay for a
Swift SDK, which changes the installation layout. Prevent this.

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -287,7 +287,7 @@ configure_file("${PROJECT_SOURCE_DIR}/cmake/config.h.in"
 add_compile_definitions($<$<OR:$<COMPILE_LANGUAGE:C>,$<COMPILE_LANGUAGE:CXX>>:HAVE_CONFIG_H>)
 
 
-if(ENABLE_SWIFT)
+if(0)
   set(INSTALL_TARGET_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>" CACHE PATH "Path where the libraries will be installed")
   set(INSTALL_DISPATCH_HEADERS_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/dispatch" CACHE PATH "Path where the headers will be installed for libdispatch")
   set(INSTALL_BLOCK_HEADERS_DIR "${CMAKE_INSTALL_LIBDIR}/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/Block" CACHE PATH "Path where the headers will be installed for the blocks runtime")
--- a/man/CMakeLists.txt
+++ b/man/CMakeLists.txt
@@ -1,6 +1,6 @@
 
 # TODO(compnerd) add symlinks
-if(NOT ENABLE_SWIFT)
+if(1)
   install(FILES
             dispatch.3
             dispatch_after.3
--- a/src/swift/CMakeLists.txt
+++ b/src/swift/CMakeLists.txt
@@ -47,7 +47,7 @@ get_swift_host_arch(swift_arch)
 install(FILES
   ${CMAKE_CURRENT_BINARY_DIR}/swift/Dispatch.swiftmodule
   ${CMAKE_CURRENT_BINARY_DIR}/swift/Dispatch.swiftdoc
-  DESTINATION ${INSTALL_TARGET_DIR}/${swift_arch})
+  DESTINATION ${INSTALL_TARGET_DIR}/swift)
 set_property(GLOBAL APPEND PROPERTY DISPATCH_EXPORTS swiftDispatch)
 install(TARGETS swiftDispatch
   EXPORT dispatchExports