Introduce Config struct

For now, it's just a container for command line arguments.

src/config.cpp

@@ -0,0 +1,28 @@
+#include "config.h"
+
+#include <string.h>
+#ifdef _WIN32
+#include <direct.h>
+#else
+#include <unistd.h>
+#endif
+
+Config::Config(int argc, char *argv[])
+{
+	for (int i = 1; i < argc; i++) {
+		if (strcmp(argv[i], "-gamedir") == 0)
+			chdir(argv[++i]);
+		else if (strcmp(argv[i], "-noantialias") == 0)
+			no_antialias = true;
+		else if (strcmp(argv[i], "-savedir") == 0)
+			save_dir = argv[++i];
+		else if (strcmp(argv[i], "-fontfile") == 0)
+			font_file = argv[++i];
+		else if (strcmp(argv[i], "-playlist") == 0)
+			playlist = argv[++i];
+		else if (strcmp(argv[i], "-fm") == 0)
+			use_fm = true;
+		else if (strcmp(argv[i], "-game") == 0)
+			game_id = argv[++i];
+	}
+}