Allow to pass environment variable for installation
@ -22,7 +22,7 @@ TEST_RUNNER = bin/picrin
CFLAGS += -I./extlib/benz/include -Wall -Wextra
LDFLAGS += -lm
prefix = /usr/local
prefix ?= /usr/local
all: CFLAGS += -O2 -DNDEBUG=1
all: bin/picrin