move endofname() to libbb

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb/endofname.c

@@ -0,0 +1,26 @@
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 2013 Denys Vlasenko
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+
+//kbuild:lib-y += endofname.o
+
+#include "libbb.h"
+
+#define is_name(c)      ((c) == '_' || isalpha((unsigned char)(c)))
+#define is_in_name(c)   ((c) == '_' || isalnum((unsigned char)(c)))
+
+const char* FAST_FUNC
+endofname(const char *name)
+{
+	if (!is_name(*name))
+		return name;
+	while (*++name) {
+		if (!is_in_name(*name))
+			break;
+	}
+	return name;
+}