The next error is :
../../../build/target/user/platform-6/libuser.a(firmware.o): In function `pulseIn(unsigned short, unsigned char)':
function_pulseIn.h:50: undefined reference to `GPIO_ReadInputDataBit'
function_pulseIn.h:57: undefined reference to `GPIO_ReadInputDataBit'
collect2: error: ld returned 1 exit status