QemuOpts: export qemu_opt_find

Export qemu_opt_find for qcow2 driver using it.
After replacing QEMUOptionParameter with QemuOpts, qcow2 driver will
use qemu_opt_find to judge if an option is explicitly set, to replace
the usage of .assigned in QEMUOptionParameter.
Signed-off-by: NChunyan Liu <cyliu@suse.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

include/qemu/option.h

@@ -130,6 +130,7 @@ char *qemu_opt_get_del(QemuOpts *opts, const char *name);
  * Returns: true if @opts includes 'help' or equivalent.
  */
 bool qemu_opt_has_help_opt(QemuOpts *opts);
+QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name);
 bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval);
 uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval);
 uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval);

util/qemu-option.c

@@ -568,7 +568,7 @@ void qemu_opts_print_help(QemuOptsList *list)
 }
 /* ------------------------------------------------------------------ */
 
-static QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name)
+QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt;