Remove legacy C locale wrapper

CMakeLists.txt

@@ -209,18 +209,6 @@ if (FMT_MASTER_PROJECT AND CMAKE_GENERATOR MATCHES "Visual Studio")
     ${CMAKE_MAKE_PROGRAM} -p:FrameworkPathOverride=\"${netfxpath}\" %*")
 endif ()
 
-set(strtod_l_headers stdlib.h)
-if (APPLE)
-  set(strtod_l_headers ${strtod_l_headers} xlocale.h)
-endif ()
-
-include(CheckSymbolExists)
-if (WIN32)
-  check_symbol_exists(_strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
-else ()
-  check_symbol_exists(strtod_l "${strtod_l_headers}" HAVE_STRTOD_L)
-endif ()
-
 function(add_headers VAR)
   set(headers ${${VAR}})
   foreach (header ${ARGN})
@@ -244,10 +232,6 @@ endif ()
 add_library(fmt ${FMT_SOURCES} ${FMT_HEADERS} README.rst ChangeLog.rst)
 add_library(fmt::fmt ALIAS fmt)
 
-if (HAVE_STRTOD_L)
-  target_compile_definitions(fmt PUBLIC FMT_LOCALE)
-endif ()
-
 if (FMT_WERROR)
   target_compile_options(fmt PRIVATE ${WERROR_FLAG})
 endif ()