Handle calloc failures

mongoose.h

@@ -233,8 +233,7 @@ typedef unsigned short uint16_t;
 typedef short int16_t;
 typedef unsigned int uint32_t;
 typedef int int32_t;
-typedef int bool;
-enum { false = 0, true = 1 };
+typedef enum { false = 0, true = 1 } bool;
 #else
 #include <stdbool.h>
 #include <stdint.h>