# You could just do:
# SRCFILES += $(shell find ccan/ -name '[a-z]*.c')
-CFLAGS=-g -O2 -Wall -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Werror -I.
+CFLAGS=-g -O3 -Wall -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Werror -I.
CFILES=$(wildcard ccan/*/[a-z]*.c)
OBJFILES=$(CFILES:.c=.o)