more Windows Makefile updates

Default to INTERNET_AVAILABLE=Y. If the build computer is not
online with the internet available, an explicit
INTERNET_AVAILABLE=N
will be required for the build, if pdcurses and Lua are not already
staged in the lib folder. That can be done by editing the appropriate line
in the Makefile, or by altering the command line:
    nmake INTERNET_AVAILABLE=N install

With Makefile.nmake:

Store pdcurses wingui and pdcurses wincon object files in separate
directories.

Rename the two pdcurses static libraries.

Because of the static library changes, the following will be required
prior to the next build:
    nmake spotless

sys/windows/Install.windows

@@ -36,7 +36,7 @@ You can use one of the following build environments:
     There are a few packaged distributions of MinGW-w64. We've tried
     out these ones, but there are likely others that will work:
 
-        MSYS2 
+        MSYS2
         - https://www.msys2.org/
         - Download the installer, and start the appropriate bash shell.
 
@@ -177,8 +177,9 @@ Setting Up
         cd sys\windows
         .\nhsetup.bat
 
-3.  From the sys\windows subfolder, change your current directory to the
-    src subfolder of the nethack source tree:
+3.  Change your current directory to the src subfolder of the nethack
+    source tree. This assumes you are still in the sys\windows folder
+    from step #2:
         cd ..\..\src
 
 4.  Edit your Makefile if you wish, but it is not required unless
@@ -191,19 +192,19 @@ Compiling
     Change your current directory to the NetHack src directory.
 
     For the Visual Studio compiler, issue these commands:
-	    nmake INTERNET_AVAILABLE=Y install
+	    nmake install
 
-    For GCC:
+    For mingw GCC:
 	Issue these commands:
-            make -f Makefile.mingw32 INTERNET_AVAILABLE=Y clean
-            make -f Makefile.mingw32 INTERNET_AVAILABLE=Y depend
-            make -f Makefile.mingw32 INTERNET_AVAILABLE=Y
+            make -f Makefile.mingw32 clean
+            make -f Makefile.mingw32 depend
+            make -f Makefile.mingw32
 
         (some older versions of mingw may require mingw32-make in
          place of plain make in the commands above)
 
     If you get any errors along the way then something has not been set
-    up correctly or you mistyped the commands shown above.
+    up correctly or perhaps you mistyped the commands shown above.
 
     The time it takes to compile depends on your particular machine of course.
     On a slower machine, you might take the opportunity to grab a beverage.
@@ -247,7 +248,7 @@ Notes:
         which should run on any 64-bit Windows O/S.
 
     **Note**: saved games and bones files are NOT compatible between the
-    32-bit and the 64-bit versions at this time. 
+    32-bit and the 64-bit versions at this time.
 
 
 /--------------------------------------------------------------\