[plt-scheme] Cygwin build trouble

At Eli's suggestion, here's the state of the Cygwin build.

I'm using a fairly recent Cygwin, although I don't know of any way to
precisely specify what version I've got.

I pulled the mzscheme sources from subversion, and wound up with
revision 355.

I configured with

        $ ./configure --prefix=/usr/local/stow/plt

Then I cd'd to the src directory, and typed "make".

That failed in mred with

    g++    -o mred mrmain.o ../mzscheme/libmzscheme.a ../mzscheme/libmzgc.a mred.o mredx.o wxGC.o wxJPEG.o wxs/libwxscheme.a wxme/libwxme.a ../wxxt/src/libwx_xt.a ../wxxt/contrib/xpm/lib/libXpm.a ../wxxt/utils/image/src/libimage_xt.a     -lXaw -lXmu -lXt -lX11 -lXext  -lpng -lz -ljpeg -lm  -liconv -lm  gmzwin.exp 
    g++: gmzwin.exp: No such file or directory

I only later realized that the README indeed says that mred doesn't
build.  But I guess I expected the Makefile to not even bother trying,
rather than trying and failing.  Oh well; no harm done.

Now I tried "make mzinstall":

    make[2]: Entering directory `/usr/local/src/plt-scheme/src/mzscheme'
    cd ..; rm -f /usr/local/stow/plt/mzscheme.exe
    cd ..; cp mzscheme/mzscheme.exe /usr/local/stow/plt/mzscheme.exe
    cp: cannot create regular file `/usr/local/stow/plt/mzscheme.exe': No such file or directory

Grr.  OK, I'll create /usr/local/stow/plt by hand.  But I must say, I
expected the Makefile to create that directory for me, since most
(every?) other package that uses autoconf does so.

After creating the directory, "make mzinstall" gets further:

    make[3]: Leaving directory `/usr/local/src/plt-scheme/src/mzscheme/dynsrc'
    cd ..; cp mzscheme/mzstart.exe `(cd /usr/local/stow/plt; pwd)`/collects/launcher/mzstart.exe
    cp: cannot create regular file `/usr/local/stow/plt/collects/launcher/mzstart.exe': No such file or directory

Same workaround: create the directory by hand.  This time "make
mzinstall" finishes.

Now to run "mzscheme.exe -mvqM- setup", from the plt directory, as the
README says.  

    setup-plt:   C:\cygwin\usr\local\src\plt-scheme\collects
    setup-plt: Pre-Installing Plot library
    plot: compiling "all" -> "C:\cygwin\usr\local\src\plt-scheme\collects/plot/compiled\native\win32\i386\libplplot.dll"...
        Compiling "all"
    "adler32.c": 
     [?,?]: Error:  C compiler did not complete successfully
    compile-extension: 
    gcc: /DHAVE_LIBPNG: No such file or directory
    gcc: /DPLD_png: No such file or directory

That looks bad.  But the build didn't stop, so perhaps it's not
important ... ?  Looks like it's trying to pass MSVC-style switches
(i.e., switches that begin with a slash, instead of a hyphen) to the
Cygwin gcc.

Scrolling down to the end of the output, to see if it worked:

    setup-plt: Updating C:\cygwin\usr\local\src\plt-scheme\collects\info-domain\compiled\cache.ss
    setup-plt: Installing MzScheme launcher C:\cygwin\usr\local\src\plt-scheme\mzc.exe
    make-embedding-executable: can't find MzScheme executable

There are a ton of similar messages.  I wonder why the build didn't
just stop after the first one ...

I think I'm stuck at this point.  For lack of anything better to do, I
tried running "./install" from the plt directory, but that merely died
like this:

    $ ./install
    install: cannot find the mzscheme executable
    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    !!               Install incomplete!               !!
    !!                                                 !!
    !! If you downloaded the source distribution, see  !!
    !!        src/README for build instructions.       !!
    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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