Added a functional version of getopt() and getopt_long(), ready for use

in our commands.

src/include/getopt.h

@@ -0,0 +1,75 @@
+#ifndef _GETOPT_H
+#define _GETOPT_H
+
+/** @file
+ *
+ * Parse command-line options
+ *
+ */
+
+#include <stddef.h>
+
+enum getopt_argument_requirement {
+	/** Option does not take an argument */
+	no_argument = 0,
+	/** Option requires an argument */
+	required_argument = 1,
+	/** Option may have an argument */
+	optional_argument = 2,
+};
+
+/** A long option, as used for getopt_long() */
+struct option {
+	/** Long name of this option */
+	const char *name;
+	/** Option takes an argument
+	 *
+	 * Must be one of @c no_argument, @c required_argument, or @c
+	 * optional_argument.
+	 */
+	int has_arg;
+	/** Location into which to store @c val, or NULL.
+	 *
+	 * See the description for @c val for more details.
+	 */
+	int *flag;
+	/** Value to return
+	 *
+	 * If @c flag is NULL, then this is the value that will be
+	 * returned by getopt_long() when this option is found, and
+	 * should therefore be set to the equivalent short option
+	 * character.
+	 *
+	 * If @c flag is non-NULL, then this value will be written to
+	 * the location pointed to by @flag, and getopt_long() will
+	 * return 0.
+	 */
+	int val;
+};
+
+extern char *optarg;
+extern int optind;
+extern int optopt;
+
+extern int getopt_long ( int argc, char * const argv[], const char *optstring,
+			 const struct option *longopts, int *longindex );
+
+/**
+ * Parse command-line options
+ *
+ * @v argv		Argument count
+ * @v argv		Argument list
+ * @v optstring		Option specification string
+ * @ret option		Option found, or -1 for no more options
+ *
+ * See getopt_long() for full details.
+ */
+static inline int getopt ( int argc, char * const argv[],
+			   const char *optstring ) {
+	static const struct option no_options[] = {
+		{ NULL, 0, NULL, 0 }
+	};
+	return getopt_long ( argc, argv, optstring, no_options, NULL );
+}
+
+#endif /* _GETOPT_H */