? lang support

Author: vinay-deshmukh

libcxx/test/std/language.support/support.limits/support.limits.general/map.version.compile.pass.cpp

@@ -32,6 +32,10 @@
 #    error "__cpp_lib_associative_heterogeneous_insertion should not be defined before c++26"
 #  endif
 
+#  ifdef __cpp_lib_constexpr_map
+#    error "__cpp_lib_constexpr_map should not be defined before c++26"
+#  endif
+
 #  ifdef __cpp_lib_containers_ranges
 #    error "__cpp_lib_containers_ranges should not be defined before c++23"
 #  endif