--- C/Makefile.orig	2019-06-26 16:49:05 UTC
+++ C/Makefile
@@ -4,7 +4,7 @@
 #  Copyright 2001-2018 Brad Lanam Walnut Creek CA, USA
 #
 
-CC = cc
+CC ?= cc
 # for tests.done
 DC = gdc
 
@@ -31,7 +31,7 @@ TEST = test
 ###
 # installation options
 #
-prefix = /usr/local
+prefix ?= /usr/local
 LOCALEDIR = $(prefix)/share/locale
 
 ###
@@ -180,7 +180,7 @@ bsd43-cc:
 	$(MAKE) _MKCONFIG_SHELL=$(MKCONFIG_SHELL) \
 		CC=cc LD=cc EXE_EXT="" OBJ_EXT=".o" \
 		DI_CFLAGS="$(DI_CFLAGS) -O" \
-		LDFLAGS="-O" di-programs
+		LDFLAGS="-O $(LDFLAGS)" di-programs
 
 .PHONY: bsd43-gcc
 bsd43-gcc:
@@ -194,7 +194,7 @@ bsd43-gcc:
 	$(MAKE) _MKCONFIG_SHELL=$(MKCONFIG_SHELL) \
 		CC=gcc LD=gcc EXE_EXT="" OBJ_EXT=".o" \
 		DI_CFLAGS="$(DI_CFLAGS) -O2" \
-		LDFLAGS="-O2" di-programs
+		LDFLAGS="-O2 $(LDFLAGS)" di-programs
 
 .PHONY: ultrix-cc
 ultrix-cc:
