diff --git a/configure.ac b/configure.ac
index 689b503b..56a02a0f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -382,6 +382,8 @@ AC_CHECK_FUNCS( setpriority )
 
 AC_CHECK_FUNCS( strerror )
 
+AC_CHECK_FUNCS( strdup )
+
 AC_CHECK_FUNCS( mkfifo, [ have_mkfifo=yes ], [ have_mkfifo=no ] )
 
 if test $fifo = "auto"; then
diff --git a/src/getlopt.c b/src/getlopt.c
index 1b315bdb..2296886b 100644
--- a/src/getlopt.c
+++ b/src/getlopt.c
@@ -10,23 +10,13 @@
 #include <stdio.h>
 #include "config.h"
 #include "getlopt.h"
+#include "compat.h"
 #include "debug.h"
 
 int loptind = 1;	/* index in argv[] */
 int loptchr = 0;	/* index in argv[loptind] */
 char *loptarg;		/* points to argument if present, else to option */
 
-#if defined(ultrix) || defined(ULTRIX)
-char *strdup (char *src)
-{
-	char *dest;
-
-	if (!(dest = (char *) malloc(strlen(src)+1)))
-		return (NULL);
-	return (strcpy(dest, src));
-}
-#endif
-
 topt *findopt (int islong, char *opt, topt *opts)
 {
 	if (!opts)
diff --git a/src/libmpg123/compat.c b/src/libmpg123/compat.c
index c081fe57..bb94aee4 100644
--- a/src/libmpg123/compat.c
+++ b/src/libmpg123/compat.c
@@ -1,7 +1,9 @@
 /*
-	compat: Some compatibility functions.
+	compat: Some compatibility functions. Basic standard C stuff, that may barely be above/around C89.
 
-	copyright 2007 by the mpg123 project - free software under the terms of the LGPL 2.1
+	The mpg123 code is determined to keep it's legacy. A legacy of old, old UNIX.
+
+	copyright 2007-8 by the mpg123 project - free software under the terms of the LGPL 2.1
 	see COPYING and AUTHORS files in distribution or http://mpg123.org
 	initially written by Thomas Orgis
 */
@@ -25,3 +27,15 @@ const char *strerror(int errnum)
 	return (errnum < sys_nerr) ?  sys_errlist[errnum]  :  "";
 }
 #endif
+
+#ifndef HAVE_STRDUP
+char *strdup(const char *src)
+{
+	char *dest;
+
+	if (!(dest = (char *) malloc(strlen(src)+1)))
+	return NULL;
+	else
+	return strcpy(dest, src);
+}
+#endif
diff --git a/src/libmpg123/compat.h b/src/libmpg123/compat.h
index 41181244..44e77d2c 100644
--- a/src/libmpg123/compat.h
+++ b/src/libmpg123/compat.h
@@ -1,7 +1,11 @@
 /*
-	compat: Some compatibility functions.
+	compat: Some compatibility functions. Basic standard C stuff, that may barely be above/around C89.
 
-	copyright 2007 by the mpg123 project - free software under the terms of the LGPL 2.1
+	The mpg123 code is determined to keep it's legacy. A legacy of old, old UNIX.
+	It is envisioned to include this compat header instead of any of the "standard" headers, to catch compatibility issues.
+	So, don't include stdlib.h or string.h ... include compat.h.
+
+	copyright 2007-8 by the mpg123 project - free software under the terms of the LGPL 2.1
 	see COPYING and AUTHORS files in distribution or http://mpg123.org
 	initially written by Thomas Orgis
 */
@@ -9,12 +13,24 @@
 #ifndef MPG123_COMPAT_H
 #define MPG123_COMPAT_H
 
+#include "config.h"
+
+#ifdef HAVE_STDLIB_H
 /* realloc, size_t */
 #include <stdlib.h>
+#endif
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
 
 void *safe_realloc(void *ptr, size_t size);
 #ifndef HAVE_STRERROR
 const char *strerror(int errnum);
 #endif
 
+#ifndef HAVE_STRDUP
+char *strdup(const char *s);
+#endif
+
 #endif