Set -mlong-calls where needed to get a static clang and lldb 3.8.0

Set -mlong-calls where needed to get a static clang and lldb 3.8.0
linking. These are too large for a branch instruction to branch from an
earlier point in the code to somewhere later.

This will also allow these to be build with Thumb-2 when we get this
infrastructure.

Reviewed by:	dim
Differential Revision:	https://reviews.freebsd.org/D4855