STM32F4

Using Arduino Microcontrollers
24 
typedef struct ArbitraryName{
         Hours_Spent;                           
         Hairs_Pulled_Out;   
}

No semicolon; perhaps the defined type name is on a subsequent line.
Without a name, gcc gives me a warning:
"foo.c:3: warning: useless storage class specifier in empty declaration"
(It still defines "struct ArbitraryName"...)