--- src/unstrip.c.orig	2017-04-27 14:26:26.000000000 +0000
+++ src/unstrip.c	2017-05-05 15:51:33.515154220 +0000
@@ -56,6 +56,15 @@
 # define _(str) gettext (str)
 #endif
 
+#ifndef strndupa
+#define strndupa(s, n) \
+       (__extension__ ({const char *__in = (s);                    \
+                        size_t __len = strnlen (__in, (n)) + 1;    \
+                        char *__out = (char *) alloca (__len);     \
+                        __out[__len-1] = '\0';                     \
+                        (char *) memcpy (__out, __in, __len-1);}))
+#endif
+
 /* Name and version of program.  */
 ARGP_PROGRAM_VERSION_HOOK_DEF = print_version;
 
