[RFA-v3] Handle cygwin wchar_t specifics

["Pierre Muller" <pierre.muller@ics-cnrs.unistra.fr>]

Here is a new version of my patch that should only
change something for Windows-OS hosts.

  This patch also changes the intermediate_encoding for mingw hosts,
  from "wchar_t" to "UTF-16LE", but this seems to work nicely
for both mingw32 and mingw64 (and only if iconv is found,
otherwise gdb_wchar_t is simply char and phony functions are used).
 
  The change might nevertheless be restricted to __CYGWIN__ only
if you think that this is a better option.

  Comments?

Pierre
 

2011-04-16  Pierre Muller  <muller@ics.u-strasbg.fr>

	Correct INTERMEDIATE_ENCODING macro setup for Windows OS using
	2 byte "wchar_t" type.
	* gdb_wchar.h (DEFAULT_INTERMEDIATE_ENCODING): New macro.
	(INTERMEDIATE_ENCODING): Change macro value to... 
	(intermediate_encoding): New external.
	* charset.c (intermediate_encoding): New variable.
	(_initialize_charset): Assign default value of intermediate_encoding
	using DEFAULT_INTERMEDAIT_ENCODING. Override this for
	Windows OS system if size of "gdb_wchar_t" type is two.
	
Index: gdb_wchar.h
===================================================================
RCS file: /cvs/src/src/gdb/gdb_wchar.h,v
retrieving revision 1.6
diff -u -p -r1.6 gdb_wchar.h
--- gdb_wchar.h	1 Jan 2011 15:33:05 -0000	1.6
+++ gdb_wchar.h	18 Apr 2011 15:07:03 -0000
@@ -79,12 +79,12 @@ typedef wint_t gdb_wint_t;
    hosts that emit a BOM when the unadorned name is used.  */
 #if defined (__STDC_ISO_10646__)
 #if WORDS_BIGENDIAN
-#define INTERMEDIATE_ENCODING "UCS-4BE"
+#define DEFAULT_INTERMEDIATE_ENCODING "UCS-4BE"
 #else
-#define INTERMEDIATE_ENCODING "UCS-4LE"
+#define DEFAULT_INTERMEDIATE_ENCODING "UCS-4LE"
 #endif
 #elif defined (_LIBICONV_VERSION) && _LIBICONV_VERSION >= 0x108
-#define INTERMEDIATE_ENCODING "wchar_t"
+#define DEFAULT_INTERMEDIATE_ENCODING "wchar_t"
 #else
 /* This shouldn't happen, because the earlier #if should have filtered
    out this case.  */
@@ -115,11 +115,14 @@ typedef int gdb_wint_t;
    also providing a phony iconv, we might as well just stick with
    "wchar_t".  */
 #ifdef PHONY_ICONV
-#define INTERMEDIATE_ENCODING "wchar_t"
+#define DEFAULT_INTERMEDIATE_ENCODING "wchar_t"
 #else
-#define INTERMEDIATE_ENCODING host_charset ()
+#define DEFAULT_INTERMEDIATE_ENCODING host_charset ()
 #endif
 
 #endif
 
+#define INTERMEDIATE_ENCODING intermediate_encoding
+extern const char *intermediate_encoding;
+
 #endif /* GDB_WCHAR_H */
Index: charset.c
===================================================================
RCS file: /cvs/src/src/gdb/charset.c,v
retrieving revision 1.43
diff -u -p -r1.43 charset.c
--- charset.c	11 Jan 2011 15:10:01 -0000	1.43
+++ charset.c	18 Apr 2011 15:07:03 -0000
@@ -206,6 +206,7 @@ phony_iconv (iconv_t utf_flag, const cha
 #define GDB_DEFAULT_TARGET_WIDE_CHARSET "UTF-32"
 #endif
 
+const char *intermediate_encoding = NULL;
 static const char *auto_host_charset_name = GDB_DEFAULT_HOST_CHARSET;
 static const char *host_charset_name = "auto";
 static void
@@ -935,7 +936,7 @@ _initialize_charset (void)
     charset_enum = default_charset_names;
 
 #ifndef PHONY_ICONV
-#ifdef HAVE_LANGINFO_CODESET
+# ifdef HAVE_LANGINFO_CODESET
   /* The result of nl_langinfo may be overwritten later.  This may
      leak a little memory, if the user later changes the host charset,
      but that doesn't matter much.  */
@@ -946,7 +947,7 @@ _initialize_charset (void)
   if (!strcmp (auto_host_charset_name, "646") || !*auto_host_charset_name)
     auto_host_charset_name = "ASCII";
   auto_target_charset_name = auto_host_charset_name;
-#elif defined (USE_WIN32API)
+# elif defined (USE_WIN32API)
   {
     /* "CP" + x<=5 digits + paranoia.  */
     static char w32_host_default_charset[16];
@@ -956,8 +957,14 @@ _initialize_charset (void)
     auto_host_charset_name = w32_host_default_charset;
     auto_target_charset_name = auto_host_charset_name;
   }
+# endif
 #endif
-#endif
+
+  intermediate_encoding = DEFAULT_INTERMEDIATE_ENCODING;
+# if defined (USE_WIN32API) || defined (__CYGWIN__)
+  if (sizeof (gdb_wchar_t) == 2)
+    intermediate_encoding = "UTF-16LE";
+# endif
 
   add_setshow_enum_cmd ("charset", class_support,
 			charset_enum, &host_charset_name, _("\