build: cmake fixes

- add EXTERNALPROJECT_OPTIONS variable to main build
- use `REQUIRED` keyword for IWYU.
- remove check_c_compiler_flag checks when `ENABLE_COMPILER_SUGGESTIONS`
  is `ON`. If we explicitly enable it then we probably want it to give
  an error if it doesn't exist, rather than silently skip it.
- Move dependency interface libraries to their find module and use them
  as a pseudo-imported target.
- Remove BUSTED_OUTPUT_TYPE. It's not used and we can reintroduce it
  again if something similar is needed.
- Use LINK_OPTIONS intead of LINK_FLAGS when generating the `--version`
  output.

cmake/FindLibintl.cmake

@@ -78,3 +78,9 @@ endif()
 find_package_handle_standard_args(Libintl DEFAULT_MSG
   ${REQUIRED_VARIABLES})
 mark_as_advanced(LIBINTL_LIBRARY LIBINTL_INCLUDE_DIR)
+
+add_library(libintl INTERFACE)
+target_include_directories(libintl SYSTEM BEFORE INTERFACE ${LIBINTL_INCLUDE_DIR})
+if (LIBINTL_LIBRARY)
+  target_link_libraries(libintl INTERFACE ${LIBINTL_LIBRARY})
+endif()

cmake/FindLibuv.cmake

@@ -61,3 +61,7 @@ find_package_handle_standard_args(Libuv DEFAULT_MSG
                                   LIBUV_LIBRARY LIBUV_INCLUDE_DIR)
 
 mark_as_advanced(LIBUV_INCLUDE_DIR LIBUV_LIBRARY)
+
+add_library(libuv INTERFACE)
+target_include_directories(libuv SYSTEM BEFORE INTERFACE ${LIBUV_INCLUDE_DIR})
+target_link_libraries(libuv INTERFACE ${LIBUV_LIBRARIES})

cmake/RunTests.cmake

@@ -32,10 +32,6 @@ if(IS_ABSOLUTE ${TEST_PATH})
   file(RELATIVE_PATH TEST_PATH "${WORKING_DIR}" "${TEST_PATH}")
 endif()
 
-if(BUSTED_OUTPUT_TYPE STREQUAL junit)
-  set(EXTRA_ARGS OUTPUT_FILE ${BUILD_DIR}/${TEST_TYPE}test-junit.xml)
-endif()
-
 set(BUSTED_ARGS $ENV{BUSTED_ARGS})
 separate_arguments(BUSTED_ARGS)
 
@@ -72,7 +68,7 @@ endif()
 execute_process(
   # Note: because of "-ll" (low-level interpreter mode), some modules like
   # _editor.lua are not loaded.
-  COMMAND ${NVIM_PRG} -ll ${WORKING_DIR}/test/lua_runner.lua ${DEPS_INSTALL_DIR} busted -v -o test.busted.outputHandlers.${BUSTED_OUTPUT_TYPE}
+  COMMAND ${NVIM_PRG} -ll ${WORKING_DIR}/test/lua_runner.lua ${DEPS_INSTALL_DIR} busted -v -o test.busted.outputHandlers.nvim
     --lazy --helper=${TEST_DIR}/${TEST_TYPE}/preload.lua
     --lpath=${BUILD_DIR}/?.lua
     --lpath=${WORKING_DIR}/runtime/lua/?.lua