While there, also modify the install target. We should make sure to
install all openlibm*.h headers. There is still some work to be done:
openlibm_fenv_*.h still depends on some additional bits. I'd propose
that we eventually create an include/openlibm_cdefs.h that contains all
of the macros we need.
I guess the idea would be to eventually also install all of the
openlibm*.h headers, instead of just openlibm.h. Make openlibm_fenv.h
suitable for this purpose by moving all of the $ARCH/fenv.h headers next
to it.
We actually need this change to make OPENLIBM_USE_HOST_FENV_H work.
Right now it's still broken, because the "#include <fenv.h>" performed
by openlibm_fenv.h still pulls in $ARCH/fenv.h as $ARCH/ is added to the
compiler include path.
I grepped through the FreeBSD source tree and for me, it seems to be
totally unclear why these two specific functions are weak references.
Such a construct is commonly used by FreeBSD's threading library
(libthr) to override certain functions, but I can't find any traces of
that.
Just use the function name directly. This fixes a compiler warning as
well (-Wmissing-prototypes).
OpenLibm has an implementation of fenv.h internally. This may be
problematic in case you want it to build against the host system's
implementation, as it would require you to somehow take the fenv.h file
out of the compiler search path.
Simply use a different naming scheme, similar to openlibm.h and
openlibm_complex.h. If we want to build against the host's fenv.h, we
can simply add an '#include <fenv.h>' from within this header.
