util: Fix compilation of envlist.c for MinGW

MinGW has no strtok_r, so we need a declaration in sysemu/os-win32.h.
We must also fix the include statements in util/envlist.c to include
that file.

We currently don't need an implementation of strtok_r because the
code is compiled but not linked for MinGW.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
bitops: unify bitops_ffsl with the one in host-utils.h, call it bitops_ctzl

We had two copies of a ffs function for longs with subtly different
semantics and, for the one in bitops.h, a confusing name: the result
was off-by-one compared to the library function ffsl.

Unify the functions into one, and solve the name problem by calling
the 0-based functions "bitops_ctzl" and "bitops_ctol" respectively.

This also fixes the build on platforms with ffsl, including Mac OS X
and Windows.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>