are very annoying --- e.g. you might decide there are several msvc
installation just because you have default location as long name, and there's
vcvars32.bat in PATH, and PATH element uses short name.
* jam_src/pathsys.h
(short_name_to_long_name): New function.
* jam_src/filent.c:
(file_dirscan): Call 'short_name_to_long_name' on argument.
* jam_src/pathunix.c:
(ShortPathToLongPath): Move here from pwd.c, and fix bugs:
'.' and '..' elements were completely broken.
(short_name_to_long_name): Implement here.
[SVN r18401]
