Fix compilation warnings in MinGW64 build using GCC 7

Reported by Richard Copley <rcopley@gmail.com>.
* src/w32heap.c (init_heap): Declare enable_lfh only for
mingw.org's MinGW build.

* src/w32console.c (w32con_write_glyphs):
* src/unexw32.c (get_section_info, COPY_CHUNK, unexec): Fix some
mismatches of data type vs format spec.

* src/w32fns.c (compute_tip_xy):
* src/w32proc.c (stop_timer_thread):
* src/w32notify.c (remove_watch):
* src/eval.c (internal_lisp_condition_case):
* src/editfns.c (Ftranslate_region_internal):
* src/data.c (Fmake_variable_buffer_local, cons_to_unsigned)
(cons_to_signed):
* src/buffer.c (fix_overlays_before): Initialize variables to
avoid compiler warnings.

* lib-src/etags.c (TeX_commands, process_file_name): Initialize
variables to avoid compilation warnings.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 2d508f35cf6..0827e9ba445 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -3764,7 +3764,7 @@ fix_overlays_before (struct buffer *bp, ptrdiff_t prev, ptrdiff_t pos)
   /* If parent is nil, replace overlays_before; otherwise, parent->next.  */
   struct Lisp_Overlay *tail = bp->overlays_before, *parent = NULL, *right_pair;
   Lisp_Object tem;
-  ptrdiff_t end;
+  ptrdiff_t end = prev;
 
   /* After the insertion, the several overlays may be in incorrect
      order.  The possibility is that, in the list `overlays_before',