Update CMake min to 3.16

- Removes FATAL_ERROR (Ignored by CMake 2.6 and higher)
- Removes redundant policy code set by new minimum
- Removes 3.15 check to simplify MSVC runtime library code
- Removes 3.16 check for objective c files

closes #2541

CMakeLists.txt

@@ -1,15 +1,7 @@
-cmake_minimum_required(VERSION 3.4...3.28 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.16...3.28)
 
 project(GLFW VERSION 3.5.0 LANGUAGES C)
 
-if (POLICY CMP0069)
-    cmake_policy(SET CMP0069 NEW)
-endif()
-
-if (POLICY CMP0077)
-    cmake_policy(SET CMP0077 NEW)
-endif()
-
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 string(COMPARE EQUAL "${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_SOURCE_DIR}" GLFW_STANDALONE)
@@ -80,24 +72,7 @@ endif()
 # This is here because it also applies to tests and examples
 #--------------------------------------------------------------------
 if (MSVC AND NOT USE_MSVC_RUNTIME_LIBRARY_DLL)
-    if (CMAKE_VERSION VERSION_LESS 3.15)
-        foreach (flag CMAKE_C_FLAGS
-                      CMAKE_C_FLAGS_DEBUG
-                      CMAKE_C_FLAGS_RELEASE
-                      CMAKE_C_FLAGS_MINSIZEREL
-                      CMAKE_C_FLAGS_RELWITHDEBINFO)
-
-            if (flag MATCHES "/MD")
-                string(REGEX REPLACE "/MD" "/MT" ${flag} "${${flag}}")
-            endif()
-            if (flag MATCHES "/MDd")
-                string(REGEX REPLACE "/MDd" "/MTd" ${flag} "${${flag}}")
-            endif()
-
-        endforeach()
-    else()
     set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
-    endif()
 endif()
 
 #--------------------------------------------------------------------

src/CMakeLists.txt

@@ -137,13 +137,6 @@ target_include_directories(glfw PRIVATE
                            "${GLFW_BINARY_DIR}/src")
 target_link_libraries(glfw PRIVATE Threads::Threads)
 
-# Workaround for CMake not knowing about .m files before version 3.16
-if (CMAKE_VERSION VERSION_LESS "3.16" AND APPLE)
-    set_source_files_properties(cocoa_init.m cocoa_joystick.m cocoa_monitor.m
-                                cocoa_window.m nsgl_context.m PROPERTIES
-                                LANGUAGE C)
-endif()
-
 if (GLFW_BUILD_WIN32)
     list(APPEND glfw_PKG_LIBS "-lgdi32")
 endif()