Include <strings.h> for ffs().

ffs() is in <strings.h> although bsd compatible systems have it in
<string.h> already.  ffs() is used in omap1.c, omap2.c, omap_i2c.c,
bt-sdp.c.  These uses can be replaced with clz32() but ffs is more
available.  Problem was spotted by malc.

Make host-utils.h formatting more consistent.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5708 c046a42c-6fe2-441c-8c8c-71466251a162