* Noweb3 compilation engineering

Noweb3 compiles on UNIX.  It produces the same PDF files as noweb2,
but it seems simpler as it seems to include its own Lua binary.  This
means it might work on Windows.  Let's try to compile it on Windows
next.

Compiling on Windows.  First, you'll need a working noweb version, so
you can't do it on Windows.  I did the tangling and weaving on UNIX
and brought the files over, but a fatal problem arises.  (See below.)

The build system is extremely unwisely written.  It should be
rewritten from scratch.  On Windows, you can't easily run shell
scripts.  Scripts should be explicitly called as ``sh script''.  The
build system should work on UNIX and Windows.

The first problem is to figure out WHY sys/wait.h is being used.
Windows doesn't have this header, I'm afraid.  Was it because of the
generation on UNIX?  I doubt it because I think Norman Ramsey did not
seriously have Windows in mind.  Must answer this question and find a
workaround.  Best approach is to code ONE CODE FOR ALL SYSTEMS.  See,
for example, Daniel J Bernstein's packages.

Icon's homepage:
https://www2.cs.arizona.edu/icon/current/

--8<---------------cut here---------------start------------->8---
%pwd
c:/emacs/tmp/noweb3/c
%make
gcc -ansi -pedantic -g -I../cii/include -I../lua-2.5+nw/include -L../cii -L../lua-2.5+nw/lib -DPLATFORM='"unix"' -Dnw_unix -DNWDEFAULTDIR='"~/tmp/nw3/lib3"' -DTEMPNAM   -c -o xpipe.o xpipe.c
In file included from xpipe.nw:560:0:
nwprocess.nw:29:13: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
             ^
nwprocess.nw:29:21: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
                     ^
nwprocess.nw:29:33: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
                                 ^
nwprocess.nw:29:44: error: unknown type name 'environ'
  _spawnvpe ((mode), (filename), (argvect), environ);
                                            ^
In file included from c:\emacs\mingw\include\unistd.h:54:0,
                 from xpipe.nw:624:
c:\emacs\mingw\include\process.h:80:42: error: conflicting types for '_spawnvpe'
 _CRTIMP intptr_t __cdecl __MINGW_NOTHROW _spawnvpe (int, const char*, const char* const*, const char* const*);
                                          ^
In file included from xpipe.nw:560:0:
nwprocess.nw:21:5: note: previous declaration of '_spawnvpe' was here
 int _spawnvpe ( int mode               /* P_WAIT or P_NOWAIT */
     ^
nwprocess.nw:31:13: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
             ^
nwprocess.nw:31:21: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
                     ^
nwprocess.nw:31:33: error: expected declaration specifiers or '...' before '(' token
  _spawnvpe ((mode), (filename), (argvect), environ);
                                 ^
nwprocess.nw:31:44: error: unknown type name 'environ'
  _spawnvpe ((mode), (filename), (argvect), environ);
                                            ^
nwprocess.nw:27:18: error: conflicting types for '_spawnvpe'
 #define spawnvpe _spawnvpe
                  ^
nwprocess.nw:21:5: note: previous declaration of '_spawnvpe' was here
 int _spawnvpe ( int mode               /* P_WAIT or P_NOWAIT */
     ^
xpipe.nw:626:22: fatal error: sys/wait.h: No such file or directory
 #include <sys/wait.h>
                      ^
compilation terminated.
<builtin>: recipe for target 'xpipe.o' failed
make: *** [xpipe.o] Error 1
%--8<---------------cut here---------------end--------------->8---