Removed the various "echo." lines from lisp\makefile.w32-in and nt\makefile.w32-in.

Removed the various "echo." lines from lisp\makefile.w32-in and nt\makefile.w32-in.
They caused mingw32-make.exe bootstrap to fail with the following error if cmd.exe
was being used as the shell:
  "process_begin: CreateProcess((null), echo., ...) failed."

I replaced the "@echo." lines in nt\makefile.w32-in with "@echo ."  This writes a .
to the screen but that is far more desirable than make bootstrap failing.

I replaced the "echo. ..." line in lisp\makefile.w32-in with "echo ;;; ...".  This
writes an extra comment line to loaddefs.el.  Again this is far more desirable than
make bootstrap failing.

NOTE: I am using cmd.exe as my shell when building Emacs with MinGW instead of
the sh.exe that comes with msys because when I use sh.exe as my shell, loaddefs.el
does not get properly generated and I get various auto load errors.