Log Message:
{,standalone-,static-}tcsh: Add build options for nls and static. Cleanup.

For tcsh and defaults for other variants, unless otherwise noted:
- Option nls enables building of NLS catalogs. Enabled by default.
- Option static enables static linking. Disabled by default.

For standalone-tcsh:
- Option static is enabled by default, except on SunOS.
- Fix building of NLS catalogs, which possibly worked at some point
  in time given the existence of the NLSDIR variable in Makefile.
- Use PLIST from tcsh, with some awk to transform the entries.
- Use DESCR from tcsh as base, with an additional local DESCR. Adjust the
  local DESCR to not say that the package is static, as that is controlled
  by an option now (and never was true for all platforms).
- Remove unnecessary DISTINFO_FILE, INSTALLATION_DIRS, and WRKSRC.

For static-tcsh:
- Option static is not available: the package is always built like tcsh
  with the static option enabled.
- Remove unnecessary DISTINFO_FILE.