* lib/msun/Makefile b/lib/msun/Makefile:
. Disconnect imprecise.c from the build. This file can be deleted.
. Add b_tgammal.c to the build for ld80 and ld128 targets. The ld128
is a 'git mv' of imprecise.c to ld128/b_tgammal.c.

* lib/msun/ld80/b_expl.c:
. New file. Implement __exp__D for ld80 targets. This is based on
bsdsrc/b_exp.c.

* lib/msun/ld80/b_logl.c:
. New file. Implement __log__D for ld80 targets. This is based on
bsdsrc/b_log.c.

* lib/msun/ld80/b_tgammal.c b/lib/msun/ld80/b_tgammal.c
. New file. Implement tgammal(x) for ld80 targets.

Submitted by: Steve Kargl
Differential Revision: https://reviews.freebsd.org/D33444
Reviewed by: pfg