build common .o files everywhere (fixes issue #29)

vector.o, nvic.o, scb.o and assert.o are available on every platform,
but at least some of them differ between the implementations. they
already got built explicityly on some platforms; now adding them to the
common Makefile.include.

lib/lpc43xx/Makefile

@@ -31,8 +31,7 @@ CFLAGS		= -O2 -g3 -Wall -Wextra -I../../include -fno-common \
 		  -mfloat-abi=hard -mfpu=fpv4-sp-d16
 # ARFLAGS	= rcsv
 ARFLAGS		= rcs
-OBJS		= gpio.o vector.o scu.o i2c.o ssp.o nvic.o systick.o \
-		  assert.o
+OBJS		= gpio.o scu.o i2c.o ssp.o
 
 VPATH += ../cm3