LCD_RW, LCD_E, LCD_RS are bit positions (from 0 to 7) on port C, usually defined by #define preprocessor statement as constants . So if you find constant definitions you will be able to recognise what pin of port C is connected to LCD controll pins .
Statements above do :
first - reset to zero pins pointed by LCD_RW and LCD_E, the rest pins stay unchanged
second - set to one pins pointed by LCD_RS and LCD_E , rest of pins stay unchanged .