libc/tests: Fix installation without MK_TOOLCHAINHEADmain

There is some exotic conditional logic here to avoid building a
particular test if a certain UBSAN library isn't present in the
toolchain sysroot.  This causes build failures for me when doing an
"installworld WITHOUT_TOOLCHAIN=", which I do frequently during tests.

I believe the problem is that SYSROOT is unset during installworld, so
the build sees the host's copy of libclang_rt.ubsan_standalone.a and
then tries to install a binary that wasn't built during buildworld.  Try
to make the check a bit less fragile.

Reviewed by:	dim
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D45035

0 files changed, 0 insertions, 0 deletions