bug#9986: libtool-2.4 and MinGW+MSYS

[Earnie]

I've found an issue with the .libs/lt-PROGRAM wrapper in that PATH is
incorrectly prepended to.  Notice below from --lt-debug output that
"\usr\src\spud\mpc-svn\bld\src\.libs:" is prepended to the windows
PATH.  The \usr\src\spud\mpc-svn\bld\src\.libs should have been
translated to e:\p\2\src\spud\mpc-svn\bld\src\.libs and a semi-colon
instead of a colon used as the path separator.

Earnie

targ.exe:./.libs/lt-targ.c:684: (lt_update_exe_path) modifying 'PATH' by
prepending
'\usr\src\spud\mpc-svn\bld\src\.libs:e:\p\2\mingw\lib:e:\p\2\mingw\bin;'
targ.exe:./.libs/lt-targ.c:634: (lt_setenv) setting 'PATH' to
'\usr\src\spud\mpc-svn\bld\src\.libs:e:\p\2\mingw\lib:e:\p\2\mingw\bin;.;e:\p\2\mingw\bin;E:\p\2\msys\bin;c:\opt\vim\vim73;c:\opt\python27;c:\opt\python27\DLLs;e:\opt\php5;e:\opt\mysql\bin;e:\opt\git\bin'
targ.exe:./.libs/lt-targ.c:705: (lt_update_lib_path) modifying 'PATH' by
prepending '\usr\src\spud\mpc-svn\bld\src\.libs:e:\p\2\mingw\lib;'
targ.exe:./.libs/lt-targ.c:634: (lt_setenv) setting 'PATH' to
'\usr\src\spud\mpc-svn\bld\src\.libs:e:\p\2\mingw\lib;\usr\src\spud\mpc-svn\bld\src\.libs:e:\p\2\mingw\lib:e:\p\2\mingw\bin;.;e:\p\2\mingw\bin;E:\p\2\msys\bin;c:\opt\vim\vim73;c:\opt\python27;c:\opt\python27\DLLs;e:\opt\php5;e:\opt\mysql\bin;e:\opt\git\bin'
targ.exe:./.libs/lt-targ.c:305: (main) lt_argv_zero:
e:/p/2/src/spud/mpc-svn/bld