SDL: cmake: detect CPU architecture in 1 compilation

https://github.com/libsdl-org/SDL/commit/bba76859f5995c351dd15c33bc3028dfc4e9ef89

From bba76859f5995c351dd15c33bc3028dfc4e9ef89 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sun, 26 May 2024 22:40:47 +0200
Subject: [PATCH] cmake: detect CPU architecture in 1 compilation

---
 .github/workflows/release.yml                 |   2 +-
 CMakeLists.txt                                |   4 +-
 .../cmake/sdl3-config-version.cmake           |   7 +-
 VisualC/pkg-support/cmake/sdl3-config.cmake   |  46 +++---
 build-scripts/build-release.py                |   1 +
 cmake/CheckCPUArchitecture.cmake              |  48 ------
 cmake/sdlcpu.cmake                            | 149 ++++++++++++++++++
 cmake/sdlplatform.cmake                       | 106 ++++---------
 8 files changed, 209 insertions(+), 154 deletions(-)
 delete mode 100644 cmake/CheckCPUArchitecture.cmake
 create mode 100644 cmake/sdlcpu.cmake

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 867fa47e63a53..6a0e3817797fb 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -330,7 +330,7 @@ jobs:
               -B build_x64 -A x64
           cmake --build build_x64 --config Release --verbose
           ctest --test-dir build_x64 --no-tests=error -C Release --output-on-failure
-      - name: 'CMake (configure + build + tests) arm64'
+      - name: 'CMake (configure + build) arm64'
         run: |
           $env:PATH += ";${{ steps.bin.outputs.path }}/x86"
           cmake -S "${{ steps.src.outputs.path }}/cmake/test"     `
diff --git a/CMakeLists.txt b/CMakeLists.txt
index af745840f17e0..3ae0c67e98bdf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -48,16 +48,16 @@ list(APPEND CMAKE_MODULE_PATH "${SDL3_SOURCE_DIR}/cmake")
 include("${SDL3_SOURCE_DIR}/cmake/macros.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/sdlchecks.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/sdlcompilers.cmake")
+include("${SDL3_SOURCE_DIR}/cmake/sdlcpu.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/sdlmanpages.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/sdlplatform.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/sdltargets.cmake")
-include("${SDL3_SOURCE_DIR}/cmake/CheckCPUArchitecture.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/GetGitRevisionDescription.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/3rdparty.cmake")
 include("${SDL3_SOURCE_DIR}/cmake/PreseedMSVCCache.cmake")
 
 SDL_DetectCompiler()
-SDL_DetectCPUArchitecture()
+SDL_DetectTargetCPUArchitectures(SDL_CPUS)
 SDL_Preseed_CMakeCache()
 
 # Increment this if there is an incompatible change - but if that happens,
diff --git a/VisualC/pkg-support/cmake/sdl3-config-version.cmake b/VisualC/pkg-support/cmake/sdl3-config-version.cmake
index f39edf85d474d..77a9541acd74e 100644
--- a/VisualC/pkg-support/cmake/sdl3-config-version.cmake
+++ b/VisualC/pkg-support/cmake/sdl3-config-version.cmake
@@ -47,8 +47,11 @@ if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "")
     set(PACKAGE_VERSION_UNSUITABLE TRUE)
 endif()
 
+include("${CMAKE_CURRENT_LIST_DIR}/sdlcpu.cmake")
+SDL_DetectTargetCPUArchitectures(_detected_archs)
+
 # check that the installed version has a compatible architecture as the one which is currently searching:
-if(NOT (CMAKE_SYSTEM_PROCESSOR MATCHES "([aA][mM][dD]64|[xX]86((_|-)64)?|[iI][34567]86|[aA][aA][rR][cC][hH]64|[aA][rR][mM]64)"))
-    set(PACKAGE_VERSION "${PACKAGE_VERSION} (x86,x64,arm64)")
+if(NOT(SDL_CPU_X86 OR SDL_CPU_X64 OR SDL_CPU_ARM64))
+    set(PACKAGE_VERSION "${PACKAGE_VERSION} (X86,X64,ARM64)")
     set(PACKAGE_VERSION_UNSUITABLE TRUE)
 endif()
diff --git a/VisualC/pkg-support/cmake/sdl3-config.cmake b/VisualC/pkg-support/cmake/sdl3-config.cmake
index 7bf3bf25f5b3a..a149e6aaf3444 100644
--- a/VisualC/pkg-support/cmake/sdl3-config.cmake
+++ b/VisualC/pkg-support/cmake/sdl3-config.cmake
@@ -30,22 +30,12 @@ endmacro()
 
 set(SDL3_FOUND TRUE)
 
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "([aA][mM][dD]64|[xX]86(_|-64)?|[iI][34567]86)")
-    if(CMAKE_SIZEOF_VOID_P EQUAL "4")
-        set(_sdl_arch_subdir "x86")
-    elseif(CMAKE_SIZEOF_VOID_P EQUAL "8")
-        set(_sdl_arch_subdir "x64")
-    else()
-        set(SDL3_FOUND FALSE)
-        return()
-    endif()
-elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "([aA][aA][rR][cC][hH]64|[aA][rR][mM]64)")
-    if(CMAKE_SIZEOF_VOID_P EQUAL "8")
-        set(_sdl_arch_subdir "arm64")
-    else()
-        set(SDL3_FOUND FALSE)
-        return()
-    endif()
+if(SDL_CPU_X86)
+    set(_sdl_arch_subdir "x86")
+elseif(SDL_CPU_X64)
+    set(_sdl_arch_subdir "x64")
+elseif(SDL_CPU_ARM64)
+    set(_sdl_arch_subdir "arm64")
 else()
     set(SDL3_FOUND FALSE)
     return()
@@ -53,11 +43,11 @@ endif()
 
 get_filename_component(_sdl3_prefix "${CMAKE_CURRENT_LIST_DIR}/.." ABSOLUTE)
 set_and_check(_sdl3_prefix      "${_sdl3_prefix}")
-set(_sdl3_include_dirs          "${_sdl3_prefix}/include;${_sdl3_prefix}/include/SDL3")
+set(_sdl3_include_dirs          "${_sdl3_prefix}/include")
 
-set(_sdl3_library     "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3.lib")
-set(_sdl3_dll_library "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3.dll")
-set(_sdl3test_library "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3_test.lib")
+set(_sdl3_implib      "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3.lib")
+set(_sdl3_dll         "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3.dll")
+set(_sdl3test_lib     "${_sdl3_prefix}/lib/${_sdl_arch_subdir}/SDL3_test.lib")
 
 unset(_sdl_arch_subdir)
 unset(_sdl3_prefix)
@@ -75,14 +65,14 @@ endif()
 set(SDL3_Headers_FOUND TRUE)
 unset(_sdl3_include_dirs)
 
-if(EXISTS "${_sdl3_library}" AND EXISTS "${_sdl3_dll_library}")
+if(EXISTS "${_sdl3_implib}" AND EXISTS "${_sdl3_dll}")
     if(NOT TARGET SDL3::SDL3-shared)
         add_library(SDL3::SDL3-shared SHARED IMPORTED)
         set_target_properties(SDL3::SDL3-shared
             PROPERTIES
                 INTERFACE_LINK_LIBRARIES "SDL3::Headers"
-                IMPORTED_IMPLIB "${_sdl3_library}"
-                IMPORTED_LOCATION "${_sdl3_dll_library}"
+                IMPORTED_IMPLIB "${_sdl3_implib}"
+                IMPORTED_LOCATION "${_sdl3_dll}"
                 COMPATIBLE_INTERFACE_BOOL "SDL3_SHARED"
                 INTERFACE_SDL3_SHARED "ON"
                 COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
@@ -93,18 +83,18 @@ if(EXISTS "${_sdl3_library}" AND EXISTS "${_sdl3_dll_library}")
 else()
     set(SDL3_SDL3-shared_FOUND FALSE)
 endif()
-unset(_sdl3_library)
-unset(_sdl3_dll_library)
+unset(_sdl3_implib)
+unset(_sdl3_dll)
 
 set(SDL3_SDL3-static_FOUND FALSE)
 
-if(EXISTS "${_sdl3test_library}")
+if(EXISTS "${_sdl3test_lib}")
     if(NOT TARGET SDL3::SDL3_test)
         add_library(SDL3::SDL3_test STATIC IMPORTED)
         set_target_properties(SDL3::SDL3_test
             PROPERTIES
                 INTERFACE_LINK_LIBRARIES "SDL3::Headers"
-                IMPORTED_LOCATION "${_sdl3test_library}"
+                IMPORTED_LOCATION "${_sdl3test_lib}"
                 COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
                 INTERFACE_SDL_VERSION "SDL3"
         )
@@ -113,7 +103,7 @@ if(EXISTS "${_sdl3test_library}")
 else()
     set(SDL3_SDL3_test_FOUND FALSE)
 endif()
-unset(_sdl3test_library)
+unset(_sdl3test_lib)
 
 if(SDL3_SDL3-shared_FOUND)
     set(SDL3_SDL3_FOUND TRUE)
diff --git a/build-scripts/build-release.py b/build-scripts/build-release.py
index 04d164647b2f2..4f89839547363 100755
--- a/build-scripts/build-release.py
+++ b/build-scripts/build-release.py
@@ -530,6 +530,7 @@ def zip_directory(zf: zipfile.ZipFile, directory: Path, arcrelpath: str):
             zip_directory(zf, directory=self.root / "include/SDL3", arcrelpath="include/SDL3")
             zip_directory(zf, directory=self.root / "docs", arcrelpath="docs")
             zip_directory(zf, directory=self.root / "VisualC/pkg-support/cmake", arcrelpath="cmake")
+            zip_file(zf, path=self.root / "cmake/sdlcpu.cmake", arcrelpath="cmake/sdlcpu.cmake")
 
             for txt in ("BUGS.txt", "README-SDL.txt", "WhatsNew.txt"):
                 zip_file(zf, path=self.root / txt, arcrelpath=txt)
diff --git a/cmake/CheckCPUArchitecture.cmake b/cmake/CheckCPUArchitecture.cmake
deleted file mode 100644
index 8e2954b93f92d..0000000000000
--- a/cmake/CheckCPUArchitecture.cmake
+++ /dev/null
@@ -1,48 +0,0 @@
-include(CheckCSourceCompiles)
-include(CMakePushCheckState)
-
-function(_internal_check_cpu_architecture macro_check NAME VARIABLE)
-  cmake_push_check_state()
-  string(TOUPPER "${NAME}" UPPER_NAME)
-  set(CACHE_VARIABLE "CHECK_CPU_ARCHITECTURE_${UPPER_NAME}")
-  set(test_src "
-int main(int argc, char *argv[]) {
-#if ${macro_check}
-  return 0;
-#else
-  choke
-#endif
-}
-")
-  check_c_source_compiles("${test_src}" "${CACHE_VARIABLE}")
-  cmake_pop_check_state()
-  if(${CACHE_VARIABLE})
-    set(${VARIABLE} "TRUE" PARENT_SCOPE)
-  else()
-    set(${VARIABLE} "FALSE" PARENT_SCOPE)
-  endif()
-endfunction()
-
-function(check_cpu_architecture ARCH VARIABLE)
-  if(ARCH STREQUAL "x86")
-    _internal_check_cpu_architecture("defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__) ||defined( __i386) || defined(_M_IX86)" x86 ${VARIABLE})
-  elseif(ARCH STREQUAL "x64")
-    _internal_check_cpu_architecture("defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64) || defined(_M_X64) || defined(_M_AMD64)" x64 ${VARIABLE})
-  elseif(ARCH STREQUAL "arm32")
-    _internal_check_cpu_architecture("defined(__arm__) || defined(_M_ARM)" arm32 ${VARIABLE})
-  elseif(ARCH STREQUAL "arm64")
-    _internal_check_cpu_architecture("defined(__aarch64__) || defined(_M_ARM64)" arm64 ${VARIABLE})
-  elseif(ARCH STREQUAL "loongarch64")
-    _internal_check_cpu_architecture("defined(__loongarch64)" loongarch64 ${VARIABLE})
-  elseif(ARCH STREQUAL "emscripten")
-    _internal_check_cpu_architecture("defined(__EMSCRIPTEN__)" emscripten ${VARIABLE})
-  elseif(ARCH STREQUAL "powerpc64")
-    _internal_check_cpu_architecture("defined(__PPC64__) || defined(__powerpc64__)" powerpc64 ${VARIABLE})
-  elseif(ARCH STREQUAL "powerpc32")
-    _internal_check_cpu_architecture("(defined(__PPC__) || defined(__powerpc__)) && !defined(__powerpc64__)" powerpc32 ${VARIABLE})
-  else()
-    message(WARNING "Unknown CPU architectures (${ARCH}).")
-    set("${VARIABLE}" FALSE)
-  endif()
-  set("${VARIABLE}" "${${VARIABLE}}" PARENT_SCOPE)
-endfunction()
diff --git a/cmake/sdlcpu.cmake b/cmake/sdlcpu.cmake
new file mode 100644
index 0000000000000..fbaa0f389de53
--- /dev/null
+++ b/cmake/sdlcpu.cmake
@@ -0,0 +1,149 @@
+function(SDL_DetectTargetCPUArchitectures DETECTED_ARCHS)
+
+  set(DETECTABLE_ARCHS ARM32 ARM64 EMSCRIPTEN LOONGARCH64 POWERPC32 POWERPC64 X86 X64)
+
+  if(APPLE AND CMAKE_OSX_ARCHITECTURES)
+    foreach(arch IN LISTS DETECTABLE_ARCHS)
+      set(SDL_CPU_${arch} "0")
+    endforeach()
+    set(detected_archs)
+    foreach(osx_arch IN LISTS CMAKE_OSX_ARCHITECTURES)
+      if(osx_arch STREQUAL "x86_64")
+        set(SDL_CPU_X64 "1")
+        list(APPEND detected_archs "X64")
+      elseif(osx_arch STREQUAL "arm64")
+        set(SDL_CPU_ARM64 "1")
+        list(APPEND detected_archs "ARM64")
+      endif()
+    endforeach()
+    set("${DETECTED_ARCHS}" "${detected_archs}" PARENT_SCOPE)
+    return()
+  endif()
+
+  set(detected_archs)
+  foreach(arch IN LISTS DETECTABLE_ARCHS)
+    if(SDL_CPU_${arch})
+      list(APPEND detected_archs "${arch}")
+    endif()
+  endforeach()
+
+  if(detected_archs)
+    set("${DETECTED_ARCHS}" "${detected_archs}" PARENT_SCOPE)
+    return()
+  endif()
+
+  set(src_arch_detect [=====[
+
+#if defined(__arm__) || defined(_M_ARM)
+#define ARCH_ARM32 "1"
+#else
+#define ARCH_ARM32 "0"
+#endif
+const char *arch_arm32 = "INFO<ARM32=" ARCH_ARM32 ">";
+
+#if defined(__aarch64__) || defined(_M_ARM64)
+#define ARCH_ARM64 "1"
+#else
+#define ARCH_ARM64 "0"
+#endif
+const char *arch_arm64 = "INFO<ARM64=" ARCH_ARM64 ">";
+
+#if defined(__EMSCRIPTEN__)
+#define ARCH_EMSCRIPTEN "1"
+#else
+#define ARCH_EMSCRIPTEN "0"
+#endif
+const char *arch_emscripten = "INFO<EMSCRIPTEN=" ARCH_EMSCRIPTEN ">";
+
+#if defined(__loongarch64)
+#define ARCH_LOONGARCH64 "1"
+#else
+#define ARCH_LOONGARCH64 "0"
+#endif
+const char *arch_loongarch64 = "INFO<LOONGARCH64=" ARCH_LOONGARCH64 ">";
+
+#if (defined(__PPC__) || defined(__powerpc__)) && !defined(__powerpc64__)
+#define ARCH_POWERPC32 "1"
+#else
+#define ARCH_POWERPC32 "0"
+#endif
+const char *arch_powerpc32 = "INFO<ARCH_POWERPC32=" ARCH_POWERPC32 ">";
+
+#if defined(__PPC64__) || defined(__powerpc64__)
+#define ARCH_POWERPC64 "1"
+#else
+#define ARCH_POWERPC64 "0"
+#endif
+const char *arch_powerpc64 = "INFO<POWERPC64=" ARCH_POWERPC64 ">";
+
+#if defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__) ||defined( __i386) || defined(_M_IX86)
+#define ARCH_X86 "1"
+#else
+#define ARCH_X86 "0"
+#endif
+const char *arch_x86 = "INFO<X86=" ARCH_X86 ">";
+
+#if defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64) || defined(_M_X64) || defined(_M_AMD64)
+#define ARCH_X64 "1"
+#else
+#define ARCH_X64 "0"
+#endif
+const char *arch_x64 = "INFO<X64=" ARCH_X64 ">";
+
+int main(int argc, char *argv[]) {
+  (void) argv;
+  int result = argc;
+  result += arch_arm32[argc];
+  result += arch_arm64[argc];
+  result += arch_emscripten[argc];
+  result += arch_loongarch64[argc];
+  result += arch_powerpc32[argc];
+  result += arch_powerpc64[argc];
+  result += arch_x86[argc];
+  result += arch_x64[argc];
+  return result;
+}
+]=====])
+
+  set(path_src_arch_detect "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CMakeTmp/SDL_detect_arch.c")
+  file(WRITE "${path_src_arch_detect}" "${src_arch_detect}")
+  set(path_dir_arch_detect "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CMakeTmp/SDL_detect_arch")
+  set(path_bin_arch_detect "${path_dir_arch_detect}/bin")
+
+  set(msg "Detecting Target CPU Architecture")
+  message(STATUS "${msg}")
+
+  try_compile(COMPILED_RES
+          "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CMakeTmp/SDL_detect_arch"
+          SOURCES "${path_src_arch_detect}"
+          COPY_FILE "${path_bin_arch_detect}"
+          )
+  if(NOT COMPILED_RES)
+    message(STATUS "${msg} - <ERROR>")
+    message(WARNING "Failed to compile source detecting the target CPU architecture")
+  endif()
+
+  set(re "INFO<([A-Z0-9]+)=([01])>")
+  file(STRINGS "${path_bin_arch_detect}" infos REGEX "${re}")
+
+  set(detected_archs)
+
+  foreach(info_arch_01 IN LISTS infos)
+    string(REGEX MATCH "${re}" A "${info_arch_01}")
+    if(NOT "${CMAKE_MATCH_1}" IN_LIST DETECTABLE_ARCHS)
+      message(WARNING "Unknown architecture: \"${CMAKE_MATCH_1}\"")
+      continue()
+    endif()
+    set(arch "${CMAKE_MATCH_1}")
+    set(arch_01 "${CMAKE_MATCH_2}")
+    if(arch_01)
+      list(APPEND detected_archs "${arch}")
+    endif()
+    set("SDL_CPU_${arch}" "${arch_01}" CACHE BOOL "Detected architecture ${arch}")
+  endforeach()
+
+  message(STATUS "${msg} - ${detected_archs}")
+
+  set("${DETECTED_ARCHS}" "${detected_archs}" PARENT_SCOPE)
+
+endfunction()
diff --git a/cmake/sdlplatform.cmake b/cmake/sdlplatform.cmake
index 76fb7586e2c40..677b187073ad2 100644
--- a/cmake/sdlplatform.cmake
+++ b/cmake/sdlplatform.cmake
@@ -1,110 +1,70 @@
-macro(SDL_DetectCMakePlatform)
-  set(SDL_CMAKE_PLATFORM )
-  # Get the platform
+function(SDL_DetectCMakePlatform)
+  set(sdl_cmake_platform )
   if(WIN32)
-    set(SDL_CMAKE_PLATFORM Windows)
+    set(sdl_cmake_platform Windows)
   elseif(PSP)
-    set(SDL_CMAKE_PLATFORM psp)
+    set(sdl_cmake_platform psp)
   elseif(APPLE)
     if(CMAKE_SYSTEM_NAME MATCHES ".*(Darwin|MacOS).*")
-      set(SDL_CMAKE_PLATFORM macOS)
+      set(sdl_cmake_platform macOS)
     elseif(CMAKE_SYSTEM_NAME MATCHES ".*tvOS.*")
-      set(SDL_CMAKE_PLATFORM tvOS)
+      set(sdl_cmake_platform tvOS)
     elseif(CMAKE_SYSTEM_NAME MATCHES ".*iOS.*")
-      set(SDL_CMAKE_PLATFORM iOS)
+      set(sdl_cmake_platform iOS)
     elseif(CMAKE_SYSTEM_NAME MATCHES ".*watchOS.*")
-      set(SDL_CMAKE_PLATFORM watchOS)
+      set(sdl_cmake_platform watchOS)
     elseif (CMAKE_SYSTEM_NAME MATCHES "visionOS")
-      set(SDL_CMAKE_PLATFORM visionOS)
+      set(sdl_cmake_platform visionOS)
     else()
       message(WARNING "Unknown Apple platform: \"${CMAKE_SYSTEM_NAME}\"")
     endif()
   elseif(CMAKE_SYSTEM_NAME MATCHES "Haiku.*")
-    set(SDL_CMAKE_PLATFORM Haiku)
+    set(sdl_cmake_platform Haiku)
   elseif(NINTENDO_3DS)
-    set(SDL_CMAKE_PLATFORM n3ds)
+    set(sdl_cmake_platform n3ds)
   elseif(PS2)
-    set(SDL_CMAKE_PLATFORM ps2)
+    set(sdl_cmake_platform ps2)
   elseif(VITA)
-    set(SDL_CMAKE_PLATFORM Vita)
+    set(sdl_cmake_platform Vita)
   elseif(CMAKE_SYSTEM_NAME MATCHES ".*Linux")
-    set(SDL_CMAKE_PLATFORM Linux)
+    set(sdl_cmake_platform Linux)
   elseif(CMAKE_SYSTEM_NAME MATCHES "kFreeBSD.*")
-    set(SDL_CMAKE_PLATFORM FreeBSD)
+    set(sdl_cmake_platform FreeBSD)
   elseif(CMAKE_SYSTEM_NAME MATCHES "kNetBSD.*|NetBSD.*")
-    set(SDL_CMAKE_PLATFORM NetBSD)
+    set(sdl_cmake_platform NetBSD)
   elseif(CMAKE_SYSTEM_NAME MATCHES "kOpenBSD.*|OpenBSD.*")
-    set(SDL_CMAKE_PLATFORM OpenBSD)
+    set(sdl_cmake_platform OpenBSD)
   elseif(CMAKE_SYSTEM_NAME MATCHES ".*GNU.*")
-    set(SDL_CMAKE_PLATFORM GNU)
+    set(sdl_cmake_platform GNU)
   elseif(CMAKE_SYSTEM_NAME MATCHES ".*BSDI.*")
-    set(SDL_CMAKE_PLATFORM BSDi)
+    set(sdl_cmake_platform BSDi)
   elseif(CMAKE_SYSTEM_NAME MATCHES "DragonFly.*|FreeBSD")
-    set(SDL_CMAKE_PLATFORM FreeBSD)
+    set(sdl_cmake_platform FreeBSD)
   elseif(CMAKE_SYSTEM_NAME MATCHES "SYSV5.*")
-    set(SDL_CMAKE_PLATFORM SYSV5)
+    set(sdl_cmake_platform SYSV5)
   elseif(CMAKE_SYSTEM_NAME MATCHES "Solaris.*|SunOS.*")
-    set(SDL_CMAKE_PLATFORM Solaris)
+    set(sdl_cmake_platform Solaris)
   elseif(CMAKE_SYSTEM_NAME MATCHES "HP-UX.*")
-    set(SDL_CMAKE_PLATFORM HPUX)
+    set(sdl_cmake_platform HPUX)
   elseif(CMAKE_SYSTEM_NAME MATCHES "AIX.*")
-    set(SDL_CMAKE_PLATFORM AIX)
+    set(sdl_cmake_platform AIX)
   elseif(CMAKE_SYSTEM_NAME MATCHES "Minix.*")
-    set(SDL_CMAKE_PLATFORM Minix)
+    set(sdl_cmake_platform Minix)
   elseif(CMAKE_SYSTEM_NAME MATCHES "Android.*")
-    set(SDL_CMAKE_PLATFORM Android)
+    set(sdl_cmake_platform Android)
   elseif(CMAKE_SYSTEM_NAME MATCHES "Emscripten.*")
-    set(SDL_CMAKE_PLATFORM Emscripten)
+    set(sdl_cmake_platform Emscripten)
   elseif(CMAKE_SYSTEM_NAME MATCHES "QNX.*")
-    set(SDL_CMAKE_PLATFORM QNX)
+    set(sdl_cmake_platform QNX)
   elseif(CMAKE_SYSTEM_NAME MATCHES "BeOS.*")
     message(FATAL_ERROR "BeOS support has been removed as of SDL 2.0.2.")
   endif()
 
-  if(SDL_CMAKE_PLATFORM)
-    string(TOUPPER "${SDL_CMAKE_PLATFORM}" _upper_platform)
-    set(${_upper_platform} TRUE)
+  if(sdl_cmake_platform)
+    string(TOUPPER "${sdl_cmake_platform}" _upper_platform)
+    set("${_upper_platform}" TRUE PARENT_SCOPE)
   else()
-    set(SDL_CMAKE_PLATFORM "unknown")
+    set(sdl_cmake_platform "unknown")
   endif()
-endmacro()
-
-function(SDL_DetectCPUArchitecture)
-  set(sdl_cpu_names)
-  if(APPLE AND CMAKE_OSX_ARCHITECTURES)
-    foreach(osx_arch ${CMAKE_OSX_ARCHITECTURES})
-      if(osx_arch STREQUAL "x86_64")
-        list(APPEND sdl_cpu_names "x64")
-      elseif(osx_arch STREQUAL "arm64")
-        list(APPEND sdl_cpu_names "arm64")
-      endif()
-    endforeach()
-  endif()
-
-  set(sdl_known_archs x64 x86 arm64 arm32 emscripten powerpc64 powerpc32 loongarch64)
-  if(NOT sdl_cpu_names)
-    set(found FALSE)
-    foreach(sdl_known_arch ${sdl_known_archs})
-      if(NOT found)
-        string(TOUPPER "${sdl_known_arch}" sdl_known_arch_upper)
-        set(var_name "SDL_CPU_${sdl_known_arch_upper}")
-        check_cpu_architecture(${sdl_known_arch} ${var_name})
-        if(${var_name})
-          list(APPEND sdl_cpu_names ${sdl_known_arch})
-          set(found TRUE)
-        endif()
-      endif()
-    endforeach()
-  endif()
-
-  foreach(sdl_known_arch ${sdl_known_archs})
-    string(TOUPPER "${sdl_known_arch}" sdl_known_arch_upper)
-    set(var_name "SDL_CPU_${sdl_known_arch_upper}")
-    if(sdl_cpu_names MATCHES "(^|;)${sdl_known_arch}($|;)")  # FIXME: use if(IN_LIST)
-      set(${var_name} 1 PARENT_SCOPE)
-    else()
-      set(${var_name} 0 PARENT_SCOPE)
-    endif()
-  endforeach()
-  set(SDL_CPU_NAMES ${sdl_cpu_names} PARENT_SCOPE)
+  set(SDL_CMAKE_PLATFORM "${sdl_cmake_platform}" PARENT_SCOPE)
 endfunction()