Minor fixes for MinGW64 build.

 configure.ac (canonical, C_SWITCH_SYSTEM): Support a 64-bit
 MinGW64 build on MS-Windows.

 nt/inc/ms-w32.h (sys_kill): Fix prototype.

 src/w32term.c (w32_initialize): Use LCID and LOWORD.
 src/w32proc.c (create_child): Use pid_t for 5th argument.
 (IsValidLocale): Don't provide prototype for MinGW64.
 (Fw32_get_valid_keyboard_layouts, Fw32_get_keyboard_layout)
 (Fw32_set_keyboard_layout): Use HKL and HIWORD/LOWORD.
 src/w32heap.c (allocate_heap) [_WIN64]: Use "ull", not "i64", which
 MinGW64 doesn't support.
 src/lisp.h (EMACS_INT) [_WIN64]: Define for the MinGW64 build.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/w32term.c b/src/w32term.c
index 583e0ebaf31..1753a9ffc9d 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -6410,9 +6410,8 @@ w32_initialize (void)
   Fset_input_mode (Qnil, Qnil, make_number (2), Qnil);
 
   {
-    DWORD input_locale_id = ((DWORD_PTR) GetKeyboardLayout (0) & 0xffffffff);
-    w32_keyboard_codepage =
-      codepage_for_locale ((LCID) (input_locale_id & 0xffff));
+    LCID input_locale_id = LOWORD (GetKeyboardLayout (0));
+    w32_keyboard_codepage = codepage_for_locale (input_locale_id);
   }
 
   /* Create the window thread - it will terminate itself when the app