add instructions for using nmake

doc/INSTALL

@@ -528,6 +528,17 @@ or in bash:
   PANDA_ROOT='C:\Cygwin'
   export PANDA_ROOT
 
+(In fact, you do not actually have to set PANDA_ROOT if Cygwin is
+installed into C:\Cygwin, since this is Panda's default behavior if
+C:\Cygwin exists.  But it's important to understand what Panda is
+doing to remap directories, and in particular that there is no
+relationship to any actual Cygwin mount points.)
+
+There is one additional point: you will need to ensure that the Visual
+Studio command-line utilities (like cl.exe) are available on your
+path.  Set your path appropriately to point to them, if necessary (or
+run vcvars32.bat to do it for you; see the paragraph below.)
+
 Follow the instructions under HOW TO BUILD PANDA FOR A UNIX
 ENVIRONMENT, above.
 
@@ -535,14 +546,17 @@ ENVIRONMENT, above.
 
 HOW TO BUILD PANDA ON A WINDOWS SYSTEM, WITHOUT CYGWIN
 
-Note: although Panda can be built without Cygwin, for the moment we
-have dropped support for the Microsoft nmake program (which is not
-really supported by Microsoft either).  Thus, even though you do not
-need to have all of Cygwin installed, you will need to have at least
-GNU make, as well as a few associated tools.  These programs are
-available from Cygwin (make.exe, sh.exe, cp.exe, rm.exe); you can copy
-these programs from someone who has installed Cygwin.  You will also
-need the support DLL, cygwin1.dll.
+You will have to make sure that you installed the command-line
+utilities on your system path when you installed Visual Studio, or you
+can run the batch file vcvars32.bat to put these utilities on your
+path for the current session (this batch file is in a directory like
+c:\Program Files\Microsoft Visual Studio .Net\Vc7\bin).
+
+Microsoft provides a command-line make utility with Visual Studio
+called nmake, although it's nowhere near as robust as the GNU make
+utility provided with Cygwin.  But Panda can generate Makefiles that
+follow the nmake convention, and will do so by default if your
+ppremake was not built with the Cygwin tools.  
 
 You will need a directory for holding the installed Panda.  This can
 be anywhere you like; the default is C:\Panda3d.  If you choose to
@@ -614,16 +628,16 @@ way you expect.
 Now that you have run ppremake, you can build the Panda3D sources.
 Begin with dtool (the current directory):
 
-  make
-  make install
+  nmake
+  nmake install
 
 Once you have successfully built and installed dtool, you can then
 build and install panda:
 
   cd \Panda3d\panda
   ppremake
-  make
-  make install
+  nmake
+  nmake install
 
 After installing panda, you are almost ready to run the program
 "pview," which is a basic model viewer program that demonstrates some
@@ -636,8 +650,8 @@ if you intend to use the Python interfaces.
 
   cd \Panda3d\direct
   ppremake
-  make
-  make install
+  nmake
+  nmake install
 
 And you may build pandatool.  You only need to build this if you want
 to take advantage of model conversion utilities for Panda like
@@ -645,8 +659,8 @@ maya2egg and egg2bam, or if you want to use other tools like pstats.
 
   cd \Panda3d\pandatool
   ppremake
-  make
-  make install
+  nmake
+  nmake install