Fix Windows build and a number of warnings

Missed in the "update patchlevel for 9.0" commit was the stupid version
hardcoding in the Windows nmake file, which broke the github windows
build.

While fixing that, I also fixed some warnings reported by the Windows
build, mostly "uninitialized" variables covered in program flow paths
which gcc is smart enough to conclude won't actually end up used
uninitialized but which the Windows compiler is not. No harm
initializing them.

Other reported warnings, I did not fix, either because it looks like
vanilla has already fixed these warnings or because if I changed them to
satisfy the Windows compiler, gcc started complaining.

src/lock.c

@@ -67,7 +67,8 @@ lock_action(void)
 static int
 picklock(void)
 {
-    coordxy doorx = u.ux + u.dx, doory = u.uy + u.dy, behind_x, behind_y;
+    coordxy doorx = u.ux + u.dx, doory = u.uy + u.dy;
+    coordxy behind_x = u.ux, behind_y = u.uy;
     boolean credit_card_slipped;
 
     if (gx.xlock.box) {

src/pager.c

@@ -1720,8 +1720,8 @@ checkfile(char *inp, struct permonst *pm, boolean user_typed_name,
             }
 
             /* database entry should exist, now find where it is */
-            long entry_offset, fseekoffset;
-            int entry_count;
+            long entry_offset = 0, fseekoffset;
+            int entry_count = 0;
             int i;
             if (found_in_file) {
                 /* skip over other possible matches for the info */

src/pickup.c

@@ -3532,7 +3532,7 @@ static boolean
 select_transfer_container(void)
 {
     char n;
-    winid win;
+    winid win = WIN_ERR;
     anything any = cg.zeroany;
     menu_item *pick_list;
     struct obj *otmp, *chosen = (struct obj *) 0;

src/worn.c

@@ -362,7 +362,7 @@ update_mon_extrinsics(
     boolean silently)
 {
     int unseen;
-    unsigned short mask;
+    unsigned short mask = 0;
     struct obj *otmp;
     int which = (int) armor_provides_extrinsic(obj),
         altwhich = altprop(obj);

sys/windows/Makefile.nmake

@@ -127,7 +127,7 @@ GIT_AVAILABLE=Y
 #==============================================================================
 #
 #  The version of the game this Makefile was designed for
-NETHACK_VERSION="8.0.0"
+NETHACK_VERSION="9.0.0"
 
 # A brief version for use in macros
 NHV=$(NETHACK_VERSION:.=)