4 files changed, 33 insertions, 1 deletions
diff --git a/Modules/CMakeOBJCCompiler.cmake.in b/Modules/CMakeOBJCCompiler.cmake.in
index 608adce..ab67bf3 100644
--- a/Modules/CMakeOBJCCompiler.cmake.in
+++ b/Modules/CMakeOBJCCompiler.cmake.in
@@ -9,6 +9,8 @@ set(CMAKE_OBJC_COMPILE_FEATURES "@CMAKE_OBJC_COMPILE_FEATURES@")
 set(CMAKE_OBJC90_COMPILE_FEATURES "@CMAKE_OBJC90_COMPILE_FEATURES@")
 set(CMAKE_OBJC99_COMPILE_FEATURES "@CMAKE_OBJC99_COMPILE_FEATURES@")
 set(CMAKE_OBJC11_COMPILE_FEATURES "@CMAKE_OBJC11_COMPILE_FEATURES@")
+set(CMAKE_OBJC17_COMPILE_FEATURES "@CMAKE_OBJC17_COMPILE_FEATURES@")
+set(CMAKE_OBJC23_COMPILE_FEATURES "@CMAKE_OBJC23_COMPILE_FEATURES@")
 
 set(CMAKE_OBJC_PLATFORM_ID "@CMAKE_OBJC_PLATFORM_ID@")
 set(CMAKE_OBJC_SIMULATE_ID "@CMAKE_OBJC_SIMULATE_ID@")
diff --git a/Modules/CMakeOBJCCompilerId.m.in b/Modules/CMakeOBJCCompilerId.m.in
index 2b8aa30..418fd48 100644
--- a/Modules/CMakeOBJCCompilerId.m.in
+++ b/Modules/CMakeOBJCCompilerId.m.in
@@ -27,6 +27,10 @@ char const* qnxnto = "INFO" ":" "qnxnto[]";
 # else
 #  define C_DIALECT
 # endif
+#elif __STDC_VERSION__ > 201710L
+# define C_DIALECT "23"
+#elif __STDC_VERSION__ >= 201710L
+# define C_DIALECT "17"
 #elif __STDC_VERSION__ >= 201000L
 # define C_DIALECT "11"
 #elif __STDC_VERSION__ >= 199901L
diff --git a/Modules/Compiler/AppleClang-OBJC.cmake b/Modules/Compiler/AppleClang-OBJC.cmake
index d4eab4f..f40c396 100644
--- a/Modules/Compiler/AppleClang-OBJC.cmake
+++ b/Modules/Compiler/AppleClang-OBJC.cmake
@@ -23,4 +23,18 @@ if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 4.0)
   set(CMAKE_OBJC11_STANDARD__HAS_FULL_SUPPORT ON)
 endif()
 
-__compiler_check_default_language_standard(OBJC 4.0 99)
+# AppleClang 10.0 was the oldest compiler available to test C17 support
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 10.0)
+  set(CMAKE_OBJC17_STANDARD_COMPILE_OPTION "-std=c17")
+  set(CMAKE_OBJC17_EXTENSION_COMPILE_OPTION "-std=gnu17")
+  set(CMAKE_OBJC17_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 11.0)
+  set(CMAKE_OBJC23_STANDARD_COMPILE_OPTION "-std=c2x")
+  set(CMAKE_OBJC23_EXTENSION_COMPILE_OPTION "-std=gnu2x")
+  set(CMAKE_OBJC23_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+# AppleClang 10.0 was the oldest compiler available to test default C11 support
+__compiler_check_default_language_standard(OBJC 4.0 99 10.0 11)
diff --git a/Modules/Compiler/Clang-OBJC.cmake b/Modules/Compiler/Clang-OBJC.cmake
index 19179e3..7a83b77 100644
--- a/Modules/Compiler/Clang-OBJC.cmake
+++ b/Modules/Compiler/Clang-OBJC.cmake
@@ -24,4 +24,16 @@ if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 3.4)
   set(CMAKE_OBJC11_STANDARD__HAS_FULL_SUPPORT ON)
 endif()
 
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 6.0)
+  set(CMAKE_OBJC17_STANDARD_COMPILE_OPTION "-std=c17")
+  set(CMAKE_OBJC17_EXTENSION_COMPILE_OPTION "-std=gnu17")
+  set(CMAKE_OBJC17_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
+if(NOT CMAKE_OBJC_COMPILER_VERSION VERSION_LESS 9.0)
+  set(CMAKE_OBJC23_STANDARD_COMPILE_OPTION "-std=c2x")
+  set(CMAKE_OBJC23_EXTENSION_COMPILE_OPTION "-std=gnu2x")
+  set(CMAKE_OBJC23_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
 __compiler_check_default_language_standard(OBJC 3.4 99 3.6 11)