Fix for building on Mac. Added README.md.

tools/unit-tests/Makefile

@@ -1,4 +1,10 @@
-LDFLAGS=-lcheck -lm -pthread -lrt -lsubunit
+LDFLAGS=-lcheck -lm -pthread
+
+UNAME_S := $(shell uname -s)
+ifneq ($(UNAME_S),Darwin)
+	LDFLAGS+=-lrt -lsubunit
+endif
+
 CFLAGS=-I../../src -I../../include
 
 all: unit-parser

tools/unit-tests/README.md

@@ -0,0 +1,22 @@
+# Unit Test Tools
+
+This uses the "check" unit test framework for C.
+
+You may need to run "apt install check", "yum install check" or "brew install check".
+
+## Building
+
+Use `make` to build.
+
+## Expected output
+
+```sh
+$ ./unit-parser
+Running suite(s): wolfBoot
+Explicit end of options reached
+This field is too large (bigger than the space available in the current header)
+This field is too large and would overflow the image header
+Illegal address (too high)
+Illegal address (too high)
+100%: Checks: 2, Failures: 0, Errors: 0
+```