Set ELF symbol type to TLS if either:

Set ELF symbol type to TLS if either:
- symbol is defined in a TLS section
- symbol is used in a TLS relocation

This is required by the GNU linker, and matches GNU as behavior.
The implementation is not as clean as it perhaps should be, but it does
the job.

Reported by: Nils Weller <nils@gnulinux.nl>

svn path=/trunk/yasm/; revision=2040