configure: Move the bz2 and zlib checks below phtreads

There are alternate implementations of those libraries that use pthreads.

configure

@@ -3834,9 +3834,6 @@ check_header VideoDecodeAcceleration/VDADecoder.h
 check_header windows.h
 check_header X11/extensions/XvMClib.h
 
-disabled  zlib || check_lib   zlib.h      zlibVersion -lz   || disable  zlib
-disabled bzlib || check_lib2 bzlib.h BZ2_bzlibVersion -lbz2 || disable bzlib
-
 if ! disabled w32threads && ! enabled pthreads; then
     check_func_headers "windows.h process.h" _beginthreadex && enable w32threads
 fi
@@ -3868,6 +3865,9 @@ for thread in $THREADS_LIST; do
     fi
 done
 
+disabled  zlib || check_lib   zlib.h      zlibVersion -lz   || disable  zlib
+disabled bzlib || check_lib2 bzlib.h BZ2_bzlibVersion -lbz2 || disable bzlib
+
 enabled sync_val_compare_and_swap && enable atomics_gcc
 enabled_all atomic_cas_ptr machine_rw_barrier && enable atomics_suncc
 enabled MemoryBarrier && enable atomics_win32