hooklib: Split out of util

This is distinct from capnhook's hooklib, although the intent is
the same. Hopefully these two libraries sharing a name won't get
too confusing...

util/meson.build

@@ -9,22 +9,12 @@ util_lib = static_library(
     sources : [
         'async.c',
         'async.h',
-        'clock.c',
-        'clock.h',
         'crc.c',
         'crc.h',
         'dprintf.c',
         'dprintf.h',
         'dump.c',
         'dump.h',
-        'fdshark.c',
-        'fdshark.h',
-        'gfx.c',
-        'gfx.h',
-        'setupapi.c',
-        'setupapi.h',
-        'spike.c',
-        'spike.h',
         'str.c',
         'str.h',
     ],