Add struct, initial create function for apple2

include/apple2.h

@@ -0,0 +1,15 @@
+#ifndef _APPLE2_H_
+#define _APPLE2_H_
+
+#include "mos6502.h"
+
+typedef struct {
+    /*
+     * The apple 2 hardware used an MOS-6502 processor.
+     */
+    mos6502 *cpu;
+} apple2;
+
+extern apple2 *apple2_create();
+
+#endif

sources.cmake

@@ -1,4 +1,5 @@
 set(emp_sources
+	apple2.c
 	log.c
 	mos6502.c
 	mos6502.addr.c

src/apple2.c

@@ -0,0 +1,20 @@
+/*
+ * apple2.c
+ */
+
+#include "apple2.h"
+
+apple2 *
+apple2_create()
+{
+    apple2 *mach;
+
+    mach = malloc(sizeof(apple2));
+    if (mach == NULL) {
+        return NULL;
+    }
+
+    mach->cpu = mos6502_create();
+    
+    return mach;
+}

tests/apple2.c

@@ -0,0 +1,12 @@
+#include <criterion/criterion.h>
+
+#include "apple2.h"
+
+Test(apple2, create)
+{
+    apple2 *mach;
+
+    mach = apple2_create();
+    cr_assert_neq(mach, NULL);
+    cr_assert_neq(mach->cpu, NULL);
+}