Also support macOS

Makefile

@@ -1,6 +1,11 @@
 .PHONY: clean install test uninstall
 
-CFLAGS ?= -std=c11 -O2 -pipe -fPIC -fno-plt -fstack-protector-strong -D_GNU_SOURCE -s -z norelro -Wall -Wextra -Wpedantic -Wfatal-errors
+CFLAGS ?= -std=c11 -O2 -pipe -fPIC -fno-plt -fstack-protector-strong -D_GNU_SOURCE -z norelro -Wall -Wextra -Wpedantic -Wfatal-errors
+UNAME_S := $(shell uname -s)
+ifeq ($(UNAME_S),Darwin)
+	CFLAGS := -std=c11 -O2 -pipe -fPIC -fstack-protector-strong -Wall -Wextra -Wpedantic -Wfatal-errors
+endif
+
 PREFIX ?= /usr
 BINDIR ?= $(PREFIX)/bin
 DESTDIR ?=

README.md

@@ -4,6 +4,8 @@
 
 `xxd` is a utility that comes with ViM. This is a standalone fork of `xxd`, a slight modernization of the C code, a slight performance increase and a drop-in replacement for `xxd`. The target platform is Linux.
 
+Tested on Arch Linux and macOS, where it builds, runs and all tests pass.
+
 ### What is it, and what can it do?
 
 The `xxd` utility is a command-line program widely used in Unix-like systems for creating a hexadecimal dump of a given binary file. Essentially, it converts binary data into a human-readable hexadecimal format, often for the purpose of debugging or examining the underlying data structure of files. It displays each byte of the input data as a two-digit hexadecimal number, often accompanied by its ASCII equivalent, if printable. Additionally, `xxd` can reverse the process, taking a hexadecimal dump and converting it back into binary.