cmake: bump minimum required CMake version to 3.16

main features:

- No more sdl-build-options/sdl-shared-build-options/sdl-global-options
- Dependency information is stored on SDL3-collector for sdl3.pc
- Use helper functions to modify the SDL targets;
    - sdl_sources to add sources
    - sdl_glob_sources to add glob soruces
    - sdl_link_dependency to add a link dependency that might also
      appear in sdl3.pc/SDL3Config.cmake
    - sdl_compile_definitions to add macro's
    - sdl_compile_options for compile options
    - sdl_include_directories for include directories
  They avoid repeated checks for existence of the SDL targets
- A nice feature of the previous is the ability to generate
  a sdl3.pc or SDL3Config.cmake that describes its dependencies
  accurately.

various:

- remove duplicate libc symbol list
- add CheckVulkan
- remove unused HAVE_MPROTECT
- add checks for getpagesize

cmake/macros.cmake

@@ -1,9 +1,5 @@
 macro(add_to_alloptions _NEWNAME)
   list(APPEND ALLOPTIONS ${_NEWNAME})
-  string(LENGTH ${_NEWNAME} _SLEN)
-  if(${LONGESTOPTIONNAME} LESS ${_SLEN})
-    set(LONGESTOPTIONNAME ${_SLEN})
-  endif()
 endmacro()
 
 macro(set_option _NAME _DESC)
@@ -27,15 +23,6 @@ macro(option_string _NAME _DESC _VALUE)
   set(HAVE_${_NAME} ${_VALUE})
 ENDMACRO()
 
-# Message Output
-macro(message_warn _TEXT)
-  message(WARNING "${_TEXT}")
-endmacro()
-
-macro(message_error _TEXT)
-  message(FATAL_ERROR "*** ERROR: ${_TEXT}")
-endmacro()
-
 macro(message_bool_option _NAME _VALUE)
   set(_PAD "\t")
   if(${ARGC} EQUAL 3)
@@ -68,27 +55,6 @@ macro(message_tested_option _NAME)
   message(STATUS "  ${_NAME}${_PAD}(Wanted: ${_REQVALUE}): ${HAVE_${_STRIPPEDNAME}}")
 endmacro()
 
-function(listtostr LIST OUTPUT)
-  if(${ARGC} EQUAL 3)
-    # prefix for each element
-    set(LPREFIX ${ARGV2})
-  else()
-    set(LPREFIX "")
-  endif()
-  # Do not use string(REPLACE ";" " ") here to avoid messing up list entries
-  set(res)
-  foreach(ITEM ${${LIST}})
-    if(ITEM MATCHES "^SHELL:")
-      string(SUBSTRING "${ITEM}" 6 -1 ITEM)
-    endif()
-    if(ITEM)
-      set(res "${res} ${LPREFIX}${ITEM}")
-    endif()
-  endforeach()
-  string(STRIP "${res}" res)
-  set(${OUTPUT} "${res}" PARENT_SCOPE)
-endfunction()
-
 function(find_stringlength_longest_item inList outLength)
   set(maxLength 0)
   foreach(item IN LISTS ${inList})
@@ -111,22 +77,9 @@ function(message_dictlist inList)
   endforeach()
 endfunction()
 
-if(CMAKE_VERSION VERSION_LESS 3.16.0 OR SDL3_SUBPROJECT)
-  # - CMake versions <3.16 do not support the OBJC language
-  # - When SDL is built as a subproject and when the main project does not enable OBJC,
-  #   CMake fails due to missing internal CMake variables (CMAKE_OBJC_COMPILE_OBJECT)
-  #   (reproduced with CMake 3.24.2)
-  macro(CHECK_OBJC_SOURCE_COMPILES SOURCE VAR)
-    set(PREV_REQUIRED_DEFS "${CMAKE_REQUIRED_DEFINITIONS}")
-    set(CMAKE_REQUIRED_DEFINITIONS "-x objective-c ${PREV_REQUIRED_DEFS}")
-    CHECK_C_SOURCE_COMPILES("${SOURCE}" ${VAR})
-    set(CMAKE_REQUIRED_DEFINITIONS "${PREV_REQUIRED_DEFS}")
-  endmacro()
-else()
+if(APPLE)
   include(CheckOBJCSourceCompiles)
-  if (APPLE)
-      enable_language(OBJC)
-  endif()
+  enable_language(OBJC)
 endif()
 
 if(CMAKE_VERSION VERSION_LESS 3.18)
@@ -156,8 +109,63 @@ if(APPLE)
   endif()
 endif()
 
-if(CMAKE_VERSION VERSION_LESS 3.13.0)
-  macro(target_link_directories _TARGET _SCOPE)
-    link_directories(${ARGN})
-  endmacro()
-endif()
+function(SDL_PrintSummary)
+  ##### Info output #####
+  message(STATUS "")
+  message(STATUS "SDL3 was configured with the following options:")
+  message(STATUS "")
+  message(STATUS "Platform: ${CMAKE_SYSTEM}")
+  message(STATUS "64-bit:   ${ARCH_64}")
+  message(STATUS "Compiler: ${CMAKE_C_COMPILER}")
+  message(STATUS "Revision: ${SDL_REVISION}")
+  message(STATUS "Vendor:   ${SDL_VENDOR_INFO}")
+  message(STATUS "")
+  message(STATUS "Subsystems:")
+
+  find_stringlength_longest_item(SDL_SUBSYSTEMS maxLength)
+  foreach(_SUB IN LISTS SDL_SUBSYSTEMS)
+    string(LENGTH ${_SUB} _SUBLEN)
+    math(EXPR _PADLEN "(${maxLength} + 1) - ${_SUBLEN}")
+    string(RANDOM LENGTH ${_PADLEN} ALPHABET " " _PADDING)
+    string(TOUPPER ${_SUB} _OPT)
+    message_bool_option(${_SUB} SDL_${_OPT} ${_PADDING})
+  endforeach()
+  message(STATUS "")
+  message(STATUS "Options:")
+  list(SORT ALLOPTIONS)
+  message_dictlist(ALLOPTIONS)
+  message(STATUS "")
+  message(STATUS " Build Shared Library: ${SDL_SHARED}")
+  message(STATUS " Build Static Library: ${SDL_STATIC}")
+  if(SDL_STATIC)
+    message(STATUS " Build Static Library with Position Independent Code: ${SDL_STATIC_PIC}")
+  endif()
+  if(APPLE)
+    message(STATUS " Build libraries as Apple Framework: ${SDL_FRAMEWORK}")
+  endif()
+  message(STATUS "")
+  if(UNIX)
+    message(STATUS "If something was not detected, although the libraries")
+    message(STATUS "were installed, then make sure you have set the")
+    message(STATUS "CMAKE_C_FLAGS and CMAKE_PREFIX_PATH CMake variables correctly.")
+    message(STATUS "")
+  endif()
+
+  if(WARN_ABOUT_ARM_SIMD_ASM_MIT)
+    message(STATUS "SDL is being built with ARM SIMD optimizations, which")
+    message(STATUS "uses code licensed under the MIT license. If this is a")
+    message(STATUS "problem, please disable that code by rerunning CMake with:")
+    message(STATUS "")
+    message(STATUS "    -DSDL_ARMSIMD=OFF")
+    message(STATUS "")
+  endif()
+
+  if(WARN_ABOUT_ARM_NEON_ASM_MIT)
+    message(STATUS "SDL is being built with ARM NEON optimizations, which")
+    message(STATUS "uses code licensed under the MIT license. If this is a")
+    message(STATUS "problem, please disable that code by rerunning CMake with:")
+    message(STATUS "")
+    message(STATUS "    -DSDL_ARMNEON=OFF")
+    message(STATUS "")
+  endif()
+endfunction()