I started composing a response a fews days ago and got
sidetracked, but it was along the same lines:
The cygwin astksh package does what it advertises -- it
builds ksh93 on cygwin. The source is all there, but the
build environment is mainly for bootstrapping, not
development.
If you want to twiddle the source and do incremental
builds then download and build the ast-base package in
/opt/ast, following the generic source instructions.
After it installs you can run the ast nmake from any
directory that contains a Makefile. nmake takes
care of recursive subdir ordering.
For those who equate different with painful: get the
aspirin out. Source miners will have to step out of all
that is gnu -- configure automake autoconf libtool.
The main difference is that the ast Makefiles are
source -- all config-type generation, prerequisite scanning,
conditional selection, local compilation conventions, etc.,
happen as a direct consequence of running the ast
nmake. Detailed discussion is welcome at
ast-users@research.att.com
Finally, to reinforce Karsten's reply, we won't retrofit
automake etc. We have source configuration
managment in place that has basically the same form
now as it did in 1990.
-- Glenn