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, 3 insertions, 3 deletions

diff --git a/src/data.c b/src/data.c
index 559844b03fd..87010e3fb28 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1823,7 +1823,7 @@ The function `default-value' gets the default value and `set-default' sets it.
   struct Lisp_Symbol *sym;
   struct Lisp_Buffer_Local_Value *blv = NULL;
   union Lisp_Val_Fwd valcontents;
-  bool forwarded;
+  bool forwarded = false;
 
   CHECK_SYMBOL (variable);
   sym = XSYMBOL (variable);
@@ -2607,7 +2607,7 @@ uintmax_t
 cons_to_unsigned (Lisp_Object c, uintmax_t max)
 {
   bool valid = false;
-  uintmax_t val;
+  uintmax_t val = max;
   if (INTEGERP (c))
     {
       valid = XINT (c) >= 0;
@@ -2661,7 +2661,7 @@ intmax_t
 cons_to_signed (Lisp_Object c, intmax_t min, intmax_t max)
 {
   bool valid = false;
-  intmax_t val;
+  intmax_t val = max;
   if (INTEGERP (c))
     {
       val = XINT (c);