Fall back to a link test for TLS in target libraries

[David Daney]

Daniel Jacobowitz wrote:
> Any thoughts on this patch?  I know that link tests can be troublesome
> in target libraries, but I'm not sure what else to do.  I recently
> tried to build GCC on an ARM LinuxThreads-only system which did not
> provide __tls_get_addr in libc.  So the compile test passed, but the
> link test would have failed, and prevented building a broken library
> (libjava in this case; the first program to fail to link was gij).
> 
> I guess one extension of it would be to check the flag set by
> GCC_NO_EXECUTABLES.
> 

I am all for it.

The main reason I added the --[enable|disable]-tls option to configure 
was because I was too lazy to write the link test.

FWIW, The exact same problem on mipsel-linux was the driving factor for 
the --disable-tls hack.

David Daney