--- Makefile.orig	2016-12-20 00:05:06.000000000 +0900
+++ Makefile	2017-11-18 08:20:31.000000000 +0900
@@ -38,8 +38,6 @@ FULL    := $(shell bin/get_version.sh --full)
 export LCOV_PERL_PATH   := /usr/bin/perl
 export LCOV_PYTHON_PATH := /usr/bin/python3
 
-PREFIX  := /usr/local
-
 FIRST_CHAR = $(shell echo "$(DESTDIR)$(PREFIX)" | cut -c 1)
 ifneq ("$(FIRST_CHAR)", "/")
 $(error "DESTDIR + PREFIX expected to be absolute path - found $(FIRST_CHAR)")