qemu-thread: Let qemu_thread_is_self() return bool

qemu_cpu_is_self(), passing the return value through, will later be
adapted to return bool as well.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
diff --git a/qemu-thread.h b/qemu-thread.h
index a78a8f2..05fdaaf 100644
--- a/qemu-thread.h
+++ b/qemu-thread.h
@@ -2,6 +2,7 @@
 #define __QEMU_THREAD_H 1
 
 #include <inttypes.h>
+#include <stdbool.h>
 
 typedef struct QemuMutex QemuMutex;
 typedef struct QemuCond QemuCond;
@@ -42,7 +43,7 @@
                         void *arg, int mode);
 void *qemu_thread_join(QemuThread *thread);
 void qemu_thread_get_self(QemuThread *thread);
-int qemu_thread_is_self(QemuThread *thread);
+bool qemu_thread_is_self(QemuThread *thread);
 void qemu_thread_exit(void *retval);
 
 #endif