CMake: avoid detection of C23 #embed on too old compilers

Related to OSGeo/PROJ#4461

Author: rouault

gdal.cmake

@@ -266,7 +266,8 @@ set(INSTALL_PLUGIN_FULL_DIR "${CMAKE_INSTALL_PREFIX}/${INSTALL_PLUGIN_DIR}")
 
 function (is_sharp_embed_available res)
     if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.21 AND
-        ((CMAKE_C_COMPILER_ID STREQUAL "GNU") OR (CMAKE_C_COMPILER_ID STREQUAL "Clang")))
+        ((CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 15.0) OR
+         (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 19.0)))
         # CMAKE_C_STANDARD=23 only supported since CMake 3.21
         set(TEST_SHARP_EMBED
           "static const unsigned char embedded[] = {\n#embed __FILE__\n};\nint main() { (void)embedded; return 0;}"