* cygtls.cc (_cygtls::remove): Eliminate compiler warning.

* dir.cc (mkdir): Check path for writability.
(rmdir): Ditto.  Remove check for special directories.
* path.cc (path_conv::check): Set PATH_RO for virtual devices.  Set error if
read-only and asked for writability.
* path.h (pathconv_arg): Add PC_WRITABLE.
(path_types): Add PATH_RO.
(path_conv::isro): Add (currently unused) check for read-only filesystem.
Return "ENOSHARE" when we know a share doesn't exist.
* include/sys/mount.h: Add MOUNT_RO flag.
* autoload.cc (WNetGetResourceInformationA): Import.
* fhandler_netdrive.cc (fhandler_netdrive::exists): Detect actual existence of
remote system rather than always assuming that it exists.

winsup/cygwin/autoload.cc

@@ -557,6 +557,8 @@ LoadDLLfuncEx (waveInStart, 4, winmm, 1)
 LoadDLLfuncEx (waveInReset, 4, winmm, 1)
 LoadDLLfuncEx (waveInClose, 4, winmm, 1)
 
+LoadDLLfunc (WNetGetResourceInformationA, 16, mpr)
+
 LoadDLLfuncEx (UuidCreate, 4, rpcrt4, 1)
 LoadDLLfuncEx (UuidCreateSequential, 4, rpcrt4, 1)
 }