diff --git a/Makefile b/Makefile
index 6444ed2..a212e69 100644
--- a/Makefile
+++ b/Makefile
@@ -8,11 +8,14 @@ PREFIX = /usr/local
 INSTALL = install
 LN = ln
 
-# ATTENTION: You may need to enable the following lines to compile F3
-#            on your platform.
-#ARGP = /usr/local
-#CFLAGS += -I$(ARGP)/include
-#LDFLAGS += -L$(ARGP)/lib -largp
+ifndef OS
+	OS = $(shell uname -s)
+endif
+ifneq ($(OS), Linux)
+	ARGP = /usr/local
+	CFLAGS += -I$(ARGP)/include
+	LDFLAGS += -L$(ARGP)/lib -largp
+endif
 
 all: $(TARGETS)
 extra: $(EXTRA_TARGETS)
diff --git a/README.rst b/README.rst
index 507a42a..a07a2ed 100644
--- a/README.rst
+++ b/README.rst
@@ -154,23 +154,17 @@ for details.
    See https://trac.macports.org/browser/trunk/dports/sysutils/f3/Portfile
    for more information.
 
-4) Set compilation flags. These following environment variables are used
-   in the Makefile to locate the argp library:
+4) Build F3::
 
-   HomeBrew::
-
-     export CFLAGS="$CFLAGS -I/usr/local/include/"
-     export LDFLAGS="$LDFLAGS -L/usr/local/lib/ -largp"
-
-   MacPorts::
-
-     export CFLAGS="$CFLAGS -I/opt/local/include/"
-     export LDFLAGS="$LDFLAGS -L/opt/local/lib/ -largp"
-
-5) Build F3::
+   When using Homebrew, you can just run::
 
        make
 
+   When using MacPorts, you will need to pass the location where MacPorts
+   installed argp-standalone::
+
+       make ARGP=/opt/local
+
 The extra applications for Linux
 --------------------------------