diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 7c0df90e822..8e4e59ac44c 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2837,6 +2837,9 @@ can be included without error when @option{-mbig-endian} is passed.
 @item stpcpy
 Target provides @code{stpcpy} function.
 
+@item strndup
+Target provides @code{strndup} function.
+
 @item sysconf
 Target supports @code{sysconf}.
 
diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
index 173e7c755f4..d02e37f79d9 100644
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-0.c
@@ -1,7 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2" } */
 /* { dg-require-effective-target size20plus } */
-/* { dg-skip-if "no strndup" { hppa*-*-hpux* } } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #include "builtin-object-size-common.h"
 
@@ -567,6 +567,7 @@ test_strdup (const char *in)
   return sz;
 }
 
+#ifndef SKIP_STRNDUP
 size_t
 __attribute__ ((noinline))
 test_strndup (const char *in, size_t bound)
@@ -577,6 +578,7 @@ test_strndup (const char *in, size_t bound)
   __builtin_free (res);
   return sz;
 }
+#endif
 
 size_t
 __attribute__ ((noinline))
@@ -589,6 +591,7 @@ test_strdup_min (const char *in)
   return sz;
 }
 
+#ifndef SKIP_STRNDUP
 size_t
 __attribute__ ((noinline))
 test_strndup_min (const char *in, size_t bound)
@@ -599,6 +602,7 @@ test_strndup_min (const char *in, size_t bound)
   __builtin_free (res);
   return sz;
 }
+#endif
 
 /* Other tests.  */
 
@@ -788,12 +792,16 @@ main (int argc, char **argv)
   const char *str = "hello world";
   if (test_strdup (str) != __builtin_strlen (str) + 1)
     FAIL ();
+#ifndef SKIP_STRNDUP
   if (test_strndup (str, 4) != 5)
     FAIL ();
+#endif
   if (test_strdup_min (str) != __builtin_strlen (str) + 1)
     FAIL ();
+#ifndef SKIP_STRNDUP
   if (test_strndup_min (str, 4) != 1)
     FAIL ();
+#endif
 
   DONE ();
 }
diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-1.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-1.c
index ffa59985024..76b4f704fed 100644
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-1.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-1.c
@@ -1,7 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
-/* { dg-skip-if "no strndup" { hppa*-*-hpux* } } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #define __builtin_object_size __builtin_dynamic_object_size
 #include "builtin-object-size-1.c"
diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-2.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-2.c
index fff32da7aea..cb757a8d699 100644
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-2.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-2.c
@@ -1,7 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
-/* { dg-skip-if "no strndup" { hppa*-*-hpux* } } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #define __builtin_object_size __builtin_dynamic_object_size
 #include "builtin-object-size-2.c"
diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-3.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-3.c
index ac223d67b10..8a12f023f27 100644
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-3.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-3.c
@@ -1,7 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
-/* { dg-skip-if "no strndup" { hppa*-*-hpux* } } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #define __builtin_object_size __builtin_dynamic_object_size
 #include "builtin-object-size-3.c"
diff --git a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-4.c b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-4.c
index fdf4284ae11..0efc2d98584 100644
--- a/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-4.c
+++ b/gcc/testsuite/gcc.dg/builtin-dynamic-object-size-4.c
@@ -1,7 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
-/* { dg-skip-if "no strndup" { hppa*-*-hpux* } } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #define __builtin_object_size __builtin_dynamic_object_size
 #include "builtin-object-size-4.c"
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-1.c b/gcc/testsuite/gcc.dg/builtin-object-size-1.c
index 4f7d4c0b370..d6d13c5ef7a 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-1.c
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #include "builtin-object-size-common.h"
 
@@ -621,7 +622,7 @@ test10 (void)
     }
 }
 
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
 /* Tests for strdup/strndup.  */
 size_t
 __attribute__ ((noinline))
@@ -709,7 +710,7 @@ test11 (void)
     FAIL ();
   free (res);
 }
-#endif /* avr */
+#endif
 
 int
 main (void)
@@ -726,7 +727,7 @@ main (void)
   test8 ();
   test9 (1);
   test10 ();
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
   test11 ();
 #endif
   DONE ();
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-2.c b/gcc/testsuite/gcc.dg/builtin-object-size-2.c
index 37d3dcc6f56..c28d72eee9b 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-2.c
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #include "builtin-object-size-common.h"
 
@@ -536,7 +537,7 @@ test8 (unsigned cond)
 #endif
 }
 
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
 /* Tests for strdup/strndup.  */
 size_t
 __attribute__ ((noinline))
@@ -624,7 +625,7 @@ test9 (void)
     FAIL ();
   free (res);
 }
-#endif /* avr */
+#endif
 
 int
 main (void)
@@ -639,7 +640,7 @@ main (void)
   test6 ();
   test7 ();
   test8 (1);
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
   test9 ();
 #endif
   DONE ();
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-3.c b/gcc/testsuite/gcc.dg/builtin-object-size-3.c
index f4d1ebf7027..3f58da3d500 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-3.c
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-3.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #include "builtin-object-size-common.h"
 
@@ -628,7 +629,7 @@ test10 (void)
     }
 }
 
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
 /* Tests for strdup/strndup.  */
 size_t
 __attribute__ ((noinline))
@@ -717,7 +718,7 @@ test11 (void)
     FAIL ();
   free (res);
 }
-#endif /* avr */
+#endif
 
 int
 main (void)
@@ -734,7 +735,7 @@ main (void)
   test8 ();
   test9 (1);
   test10 ();
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
   test11 ();
 #endif
   DONE ();
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-4.c b/gcc/testsuite/gcc.dg/builtin-object-size-4.c
index 2887dd15042..b3eb36efb74 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-4.c
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-4.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -Wno-stringop-overread" } */
 /* { dg-require-effective-target alloca } */
+/* { dg-additional-options "-DSKIP_STRNDUP" { target { ! strndup } } } */
 
 #include "builtin-object-size-common.h"
 
@@ -509,7 +510,7 @@ test8 (unsigned cond)
 #endif
 }
 
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
 /* Tests for strdup/strndup.  */
 size_t
 __attribute__ ((noinline))
@@ -597,7 +598,7 @@ test9 (void)
     FAIL ();
   free (res);
 }
-#endif /* avr */
+#endif
 
 int
 main (void)
@@ -612,7 +613,7 @@ main (void)
   test6 ();
   test7 ();
   test8 (1);
-#if !defined(__AVR__) && !defined(__hpux__) /* avr and hpux have no strndup */
+#ifndef SKIP_STRNDUP
   test9 ();
 #endif
   DONE ();
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 938fff9392c..3a5713d9869 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -11581,6 +11581,17 @@ proc check_effective_target_stpcpy {} {
     return [check_function_available "stpcpy"]
 }
 
+# Returns 1 if "strndup" is available on the target system.
+
+proc check_effective_target_strndup {} {
+    if { [istarget *-*-vxworks*] } {
+	# VxWorks doesn't have strndup but our way to test fails
+	# to detect as we're doing partial links for kernel modules.
+	return 0
+    }
+    return [check_function_available "strndup"]
+}
+
 # Returns 1 if "sigsetjmp" is available on the target system.
 # Also check if "__sigsetjmp" is defined since that's what glibc
 # uses.