diff -uNr haproxy-2.3.1/Makefile haproxy-2.3.1.mod/Makefile
--- haproxy-2.3.1/Makefile	2020-11-13 20:20:03.000000000 +0000
+++ haproxy-2.3.1.mod/Makefile	2020-11-23 13:37:28.797578825 +0000
@@ -134,10 +134,10 @@
 
 #### Installation options.
 DESTDIR =
-PREFIX = /usr/local
-SBINDIR = $(PREFIX)/sbin
+PREFIX ?= /usr/local
+SBINDIR = $(PREFIX)/bin
 MANDIR = $(PREFIX)/share/man
-DOCDIR = $(PREFIX)/doc/haproxy
+DOCDIR = $(PREFIX)/share/doc/haproxy
 
 #### TARGET system
 # Use TARGET=<target_name> to optimize for a specific target OS among the
@@ -161,7 +161,7 @@
 ARCH =
 
 #### Toolchain options.
-CC = cc
+CC ?= cc
 LD = $(CC)
 
 #### Debug flags (typically "-g").