Remove grantpt.c, which should have been deleted in the MPSAFE TTY commit.
Remove grantpt.c, which should have been deleted in the MPSAFE TTY commit.

The routines in grantpt.c have been moved to ptsname.c in the MPSAFE TTY
layer, because grantpt() is now effectively a no-op. I forgot to remove
the corresponding source file from libc.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase