Add munit for unit testing.

Main method extracted to separate file to make it easier to test the _rest_ of the code.
munit is added as a submodule by running `cd src; git submodule add https://github.com/nemequ/munit.git` .

Unit testing has so far only been tested on ubuntu.

src/test/Makefile

@@ -0,0 +1,75 @@
+# Using µnit is very simple; just include the header and add the C
+# file to your sources.  That said, here is a simple Makefile to build
+# the example.
+
+CSTD:=99
+OPENMP:=n
+ASAN:=n
+UBSAN:=n
+EXTENSION:=
+TEST_ENV:=
+CFLAGS:=-Wall -Wno-char-subscripts -Wno-unused-but-set-variable
+AGGRESSIVE_WARNINGS=n
+LIBS:=-lcrypt 
+
+#ifeq ($(CC),pgcc)
+#        CFLAGS+=-c$(CSTD)
+#else
+#        CFLAGS+=-std=c$(CSTD)
+#endif
+
+ifeq ($(OPENMP),y)
+        ifeq ($(CC),pgcc)
+                CFLAGS+=-mp
+        else
+                CFLAGS+=-fopenmp
+        endif
+endif
+
+ifneq ($(SANITIZER),)
+        CFLAGS+=-fsanitize=$(SANITIZER)
+endif
+
+ifneq ($(CC),pgcc)
+        ifeq ($(EXTRA_WARNINGS),y)
+                CFLAGS+=-Wall -Wextra -Werror
+        endif
+
+        ifeq ($(ASAN),y)
+                CFLAGS+=-fsanitize=address
+        endif
+
+        ifeq ($(UBSAN),y)
+                CFLAGS+=-fsanitize=undefined
+        endif
+endif
+
+MUNIT_FILES := ../munit/munit.h ../munit/munit.c
+TEST_FILES := $(ls *.c)
+
+# exclude main.c to avoid having multiple entrypoints.
+OBJ_FILES_FROM_MUD_CODE != ls ../*.c | grep -v main.c | sed 's/\.c$$/.o/g' | xargs
+OBJ_FILES_FORM_MUNIT:= ../munit/munit.o
+OBJ_FILES_FROM_TESTS!= ls *.c | sed 's/\$$.c/.o/g' | xargs
+
+OBJ_FILES := $(OBJ_FILES_FROM_MUD_CODE) $(OBJ_FILES_FORM_MUNIT) $(OBJ_FILES_FROM_TESTS) $(LIBS)
+
+testfile: $(OBJ_FILES)
+	$(CC) $(CFLAGS) -o testfile $(OBJ_FILES)
+
+test: testfile
+	$(TEST_ENV) ./testfile
+
+$%.o: %.c
+	$(CC) $< $(CFLAGS) -c -o $@ 
+
+clean:
+	rm -f *.o testfile depend
+all: test
+
+default: all
+
+depend:
+	$(CC) -MM *.c > depend
+
+-include depend