patch 8.0.0173: build fails with EBCDIC defined

Problem:    When compiling with EBCDIC defined the build fails. (Yaroslav
            Kuzmin)
Solution:   Move sortFunctions() to the right file.  Avoid warning for
            redefining __SUSV3.
diff --git a/src/os_unixx.h b/src/os_unixx.h
index f1aad2c..c83ea31 100644
--- a/src/os_unixx.h
+++ b/src/os_unixx.h
@@ -113,7 +113,7 @@
 
 /* shared library access */
 #if defined(HAVE_DLFCN_H) && defined(USE_DLOPEN)
-# ifdef __MVS__
+# if defined(__MVS__) && !defined (__SUSV3)
     /* needed to define RTLD_LAZY (Anthony Giorgio) */
 #  define __SUSV3
 # endif