1. modify this line to
#ifndef isb()
#define isb() asm volatile ("isb" : : : "memory)
#warning "isb() not defined somewhere else!"
#endif 

2. add a new header 'asm-arm_inline.h' and add the following line

#define isb() asm volatile ("isb" : : : "memory)

3. #include 'asm-arm_inline.h' in this file