(LINK_EXTENSION): New macro.
(check_existence): New static function.
(find_on_path): Check for symbolic links if asked.
(dll_info): New error handling.
(track_down): Only call dll_info() for executables, display
an error for symlinks, and print magic number for others.
(find_app_on_path): New static function.
(cygcheck, dump_sysinfo): Call find_app_on_path() instead of
find_on_path().
* path.cc (cmp_shortcut_header): New static function.
(get_word, get_dword): Moved from cygcheck.cc.
(EXE_MAGIC, SHORTCUT_MAGIC, SYMLINK_COOKIE, SYMLINK_MAGIC): New
macros.
(is_exe, is_symlink, readlink): New functions.
* path.h (is_exe, is_symlink, readlink): Declare.
(get_word, get_dword): Ditto.
cea9b62102