Include stdbool.h

Needed for older GCC versions.

Author: bartoldeman

src/base/emu-i386/simx86/interval-tree.c

@@ -2,6 +2,7 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include "interval-tree.h"
 
 #ifndef likely