Update.

* elf/Makefile (tests): Add $(tests-nodelete-$(have-z-nodelete)).
	(tests-nodelete-yes): Define.
	(modules-names): Add $(modules-nodelete-$(have-z-nodelete)).
	Add rules to build nodelete and modules.
	* elf/nodelete.c: New file.
	* elf/nodelmod1.c: New file.
	* elf/nodelmod2.c: New file.
	* configure.in: Add test for -z nodelete option.
	* config.make.in: Define have-z-nodelete with libc_cv_z_nodelete.

elf/nodelete.c

@@ -0,0 +1,140 @@
+#include <dlfcn.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+
+
+static sigjmp_buf jmpbuf;
+
+
+static void
+handler (int sig)
+{
+  siglongjmp (jmpbuf, 1);
+}
+
+
+#define TEST_FUNCTION do_test ()
+static int
+do_test (void)
+{
+  /* We are testing the two possibilities to mark an object as not deletable:
+     - marked on the linker commandline with `-z nodelete'
+     - with the RTLD_NODELETE flag at dlopen()-time.
+
+     The test we are performing should be safe.  We are loading the objects,
+     get the address of variables in the respective object, unload the object
+     and then try to read the variable.  If the object is unloaded this
+     should lead to an segmentation fault.  */
+  int result = 0;
+  void *p;
+  struct sigaction sa;
+
+  sa.sa_handler = handler;
+  sigfillset (&sa.sa_mask);
+  sa.sa_flags = SA_RESTART;
+  sa.sa_restorer = NULL;
+
+  if (sigaction (SIGSEGV, &sa, NULL) == -1)
+    printf ("cannot install signal handler: %m\n");
+
+  p = dlopen ("nodelmod1.so", RTLD_LAZY);
+  if (p == NULL)
+    {
+      puts ("failed to load \"nodelmod1.so\"");
+      result = 1;
+    }
+  else
+    {
+      int *varp;
+
+      puts ("succeeded loading \"nodelmod1.so\"");
+
+      varp = dlsym (p, "var1");
+      if (varp == NULL)
+	{
+	  puts ("failed to get address of \"var1\" in \"nodelmod1.so\"");
+	  result = 1;
+	}
+      else
+	{
+	  *varp = 20000720;
+
+	  /* Now close the object.  */
+	  if (dlclose (p) != 0)
+	    {
+	      puts ("failed to close \"nodelmod1.so\"");
+	      result = 1;
+	    }
+	  else if (! sigsetjmp (jmpbuf, 1))
+	    {
+	      /* Access the variable again.  */
+	      if (*varp != 20000720)
+		{
+		  puts ("\"var1\" value not correct");
+		  result = 1;
+		}
+	      else
+		puts ("-z nodelete test succeeded");
+	    }
+	  else
+	    {
+	      /* We caught an segmentation fault.  */
+	      puts ("\"nodelmod1.so\" got deleted");
+	      result = 1;
+	    }
+	}
+    }
+
+  p = dlopen ("nodelmod2.so", RTLD_LAZY | RTLD_NODELETE);
+  if (p == NULL)
+    {
+      puts ("failed to load \"nodelmod2.so\"");
+      result = 1;
+    }
+  else
+    {
+      int *varp;
+
+      puts ("succeeded loading \"nodelmod2.so\"");
+
+      varp = dlsym (p, "var2");
+      if (varp == NULL)
+	{
+	  puts ("failed to get address of \"var2\" in \"nodelmod2.so\"");
+	  result = 1;
+	}
+      else
+	{
+	  *varp = 42;
+
+	  /* Now close the object.  */
+	  if (dlclose (p) != 0)
+	    {
+	      puts ("failed to close \"nodelmod2.so\"");
+	      result = 1;
+	    }
+	  else if (! sigsetjmp (jmpbuf, 1))
+	    {
+	      /* Access the variable again.  */
+	      if (*varp != 42)
+		{
+		  puts ("\"var2\" value not correct");
+		  result = 1;
+		}
+	      else
+		puts ("RTLD_NODELETE test succeeded");
+	    }
+	  else
+	    {
+	      /* We caught an segmentation fault.  */
+	      puts ("\"nodelmod2.so\" got deleted");
+	      result = 1;
+	    }
+	}
+    }
+
+  return result;
+}
+
+#include "../test-skeleton.c"