bug#11578: 24.1.50; Can't 'make install' on Windows

[Kazuhiro Ito <kzhr@d1.dion.ne.jp>]

When I run configure.bat with --prefix option, 'make install' with
MinGW fails.

> make: Circular D:/bin/emacs_trunk <- D:/bin/emacs_trunk dependency dropped.
> make   -C ../lib-src install
> [Please ignore a syntax error on the next line - it is intentional]
> /bin/sh: -c: line 0: unexpected EOF while looking for matching `"'
> /bin/sh: -c: line 1: syntax error: unexpected end of file
> make[1]: Entering directory `/f/build/emacs-trunk/lib-src'
> mkdir "D:/bin/emacs_trunk /bin"
> mkdir: cannot create directory `D:/bin/emacs_trunk /bin': No such file or directory
> make[1]: [install] Error 1 (ignored)
> cp -f oo-spd/i386/etags.exe D:/bin/emacs_trunk /bin
> cp: omitting directory `D:/bin/emacs_trunk'
> make[1]: *** [install] Error 1
> make[1]: Leaving directory `/f/build/emacs-trunk/lib-src'
> make: *** [install-other-dirs-gmake] Error 2

In the above, 'D:/bin/emacs_trunk' is argument of --prefix option.  It
seems that makefile.w32-in does not assume INSTALL_DIR has trailing
space.

-- 
Kazuhiro Ito