* sigproc.cc (sigproc_terminate): Don't close sendsig handle when execing since

* sigproc.cc (sigproc_terminate): Don't close sendsig handle when execing since
we're not closing what we think we're closing.
(sig_send): Improve debugging when exiting due to no_signals_available.
* wincap.h (wincaps::cant_debug_dll_entry): New element.
* wincap.cc: Implement above element throughout.
* dcrt0.cc (initial_env): Accommodate changes necessary to allow initial
debugging for systems which do not allow debugging in dll_entry.
(dll_crt0_0): Add initial_env call back here.
* Makefile.in (install-man): Use mandir as target for installation.
* include/cygwin/version.h: Bump DLL minor number to 7 (should have been done
earlier).