[Ada] Adding support for Ada.Locales package

This patch adds generic support for the Ada.Locales package that
relies on the setlocale() C service.

2018-05-22  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* locales.c: New implementation for the Ada.Locales package.
	* libgnat/a-locale.ads: Remove comment indicating that this is not
	implemented.
	* doc/gnat_rm/standard_library_routines.rst: Remove comment indicating
	that this is not implemented.
	* gnat_rm.texi: Regenerate.

From-SVN: r260509

gcc/ada/ChangeLog

+2018-05-22  Javier Miranda  <miranda@adacore.com>
+
+	* locales.c: New implementation for the Ada.Locales package.
+	* libgnat/a-locale.ads: Remove comment indicating that this is not
+	implemented.
+	* doc/gnat_rm/standard_library_routines.rst: Remove comment indicating
+	that this is not implemented.
+	* gnat_rm.texi: Regenerate.
+
 2018-05-22  Hristian Kirtchev  <kirtchev@adacore.com>
 
 	* exp_ch5.adb, freeze.adb, pprint.adb, sem_ch4.adb, sem_res.adb: Minor

gcc/ada/doc/gnat_rm/standard_library_routines.rst

@@ -273,9 +273,7 @@ the unit is not implemented.
 
 ``Ada.Locales`` *(A.19)*
   This package provides declarations providing information (Language
-  and Country) about the current locale. This package is currently not
-  implemented other than by providing stubs which will always return
-  Language_Unknown/Country_Unknown.
+  and Country) about the current locale.
 
 
 ``Ada.Numerics``

gcc/ada/gnat_rm.texi

@@ -20617,9 +20617,7 @@ This package provides a generic interface to generalized iterators.
 @item @code{Ada.Locales} @emph{(A.19)}
 
 This package provides declarations providing information (Language
-and Country) about the current locale. This package is currently not
-implemented other than by providing stubs which will always return
-Language_Unknown/Country_Unknown.
+and Country) about the current locale.
 
 @item @code{Ada.Numerics}
 

gcc/ada/libgnat/a-locale.ads

@@ -15,10 +15,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
---  Note that this package is currently not implemented on any platform and
---  functions Language and Country will always return
---  Language_Unknown/Country_Unknown.
-
 package Ada.Locales is
    pragma Preelaborate (Locales);
    pragma Remote_Types (Locales);