Merge branch 'xlocale-checks'

Fix build on systems which don't have full x-locale support even though they
do have <xlocale.h>, such as OpenIndiana.

Closes https://github.com/wxWidgets/wxWidgets/pull/461

configure.in

@@ -4117,7 +4117,9 @@ if test "$TOOLKIT" != "MSW"; then
 
 dnl check for available version of iconv()
 if test "$wxUSE_LIBICONV" != "no" ; then
+    AC_LANG_PUSH(C++)
     AM_ICONV
+    AC_LANG_POP()
     LIBS="$LIBICONV $LIBS"
 fi
 
@@ -5719,10 +5721,31 @@ if test "$wxUSE_INTL" = "yes" ; then
 fi
 
 if test "$wxUSE_XLOCALE" = "yes" ; then
-    AC_DEFINE(wxUSE_XLOCALE)
-    AC_CHECK_TYPES(locale_t,,,
-                   [#include <xlocale.h>
-                    #include <locale.h>])
+    dnl even if xlocale.h exists, it may not contain all that
+    dnl wx needs. check if strtod_l() really is available.
+    AC_CACHE_CHECK([for complete xlocale],
+                   wx_cv_func_strtod_l,
+    [
+        AC_LANG_PUSH(C++)
+        AC_TRY_COMPILE(
+        [
+        #include <xlocale.h>
+        #include <locale.h>
+        #include <stdlib.h>
+        ],
+        [
+        locale_t t;
+        strtod_l(NULL, NULL, t);
+        ],
+        wx_cv_func_strtod_l=yes,
+        wx_cv_func_strtod_l=no
+        )
+        AC_LANG_POP()
+    ])
+
+    if test "$wx_cv_func_strtod_l" = "yes" ; then
+        AC_DEFINE(wxUSE_XLOCALE)
+    fi
 fi
 
 if test "$wxUSE_LOG" = "yes"; then