Use libnss_files.so for tests posix/bug-ga2 and resolv/tst-leaks2 [BZ #26821]

The tests posix/bug-ga2-mem and resolv/mtrace-tst-leaks2 are failing on
fedora 33 as mtrace reports memory leaks.

The /etc/nsswitch.conf differs between
Fedora 32: hosts:      files dns myhostname
Fedora 33: hosts:      files resolve [!UNAVAIL=return] myhostname dns

Therefore /lib64/libnss_resolve.so.2 (from systemd) and the dependencies
libgcc_s.so.1 and libpthread.so.0 are loaded.

Usually all malloc'ed resources from getaddrinfo / gethostbyname are freed
and the libraries are dlclose'd in nss/nsswitch.c:libc_freeres_fn (free_mem).
Unfortunately, /lib64/libnss_resolve.so.2 is marked with DF_1_NODELETE.
As this library is not unmapped, you'll see "Memory not freed".

Therefore those tests are now only relying on libnss_files.so by making
them test-container tests and providing the required configuration files.

By moving the tests to tests-container, those are now running with
"make check".  Therefore the mtrace part of the tests are also moved
from "make xcheck" to "make check".

bug-ga2.c is now using test-driver.c in order to support WAIT_FOR_DEBUGGER
environment variable.

1 files changed, 4 insertions, 2 deletions

diff --git a/resolv/tst-leaks2.c b/resolv/tst-leaks2.c
index a2f5db3adc..49a5d11d49 100644
--- a/resolv/tst-leaks2.c
+++ b/resolv/tst-leaks2.c
@@ -21,6 +21,7 @@
 #include <mcheck.h>
 #include <netdb.h>
 #include <resolv.h>
+#include <support/check.h>
 
 static int
 do_test (void)
@@ -28,8 +29,9 @@ do_test (void)
   mtrace ();
   for (int i = 0; i < 20; ++i)
     {
-      res_init ();
-      gethostbyname ("www.gnu.org");
+      TEST_VERIFY_EXIT (res_init () == 0);
+      if (gethostbyname ("www.gnu.org") == NULL)
+	FAIL_EXIT1 ("%s\n", hstrerror (h_errno));
     }
   return 0;
 }