/^LIBS_MAIL *=/s/@[^@\n]*@//g
/^LIBS_SYSTEM *=/s/@[^@\n]*@//g
/^LIB_CLOCK_GETTIME *=/s/@[^@\n]*@//g
+/^LIB_TIMER_TIME *=/s/@[^@\n]*@//g
/^CFLAGS *=/s!=.*$!=-O2 -g!
/^C_SWITCH_SYSTEM *=/s!=.*$!=-DMSDOS -I../msdos!
/^C_SWITCH_MACHINE *=/s/@C_SWITCH_MACHINE@//