$NetBSD$

Support variable PREFIX (without modification)

--- Makefile.orig	2019-10-25 23:09:16.000000000 +0000
+++ Makefile
@@ -10,7 +10,8 @@
 #
 .SUFFIXES : .ml .mli .cmo .cmi .cmx .mly
 
-INSTALL_DIR=/usr/local
+PREFIX?=/usr/local
+INSTALL_DIR=$(PREFIX)
 INSTALL_BIN_DIR=$(INSTALL_DIR)/bin
 INSTALL_LIB_DIR=$(INSTALL_DIR)/lib/haxe
 INSTALL_STD_DIR=$(INSTALL_DIR)/share/haxe/std