require et random_device for cons token test

[Alexandre Oliva <oliva@adacore.com>]

On target systems that don't support any random_device, not even the
default one, other random_device constructor tests are disabled by
dg-require-effective-target random_device.  The token.cc also
exercises the default constructor, in a way that doesn't expect an
exception to be raised, but it's not guarded by the same requirement.

Other potentially-raising ctors in token.cc expect exceptions and
handle them, but the ("default")-constructed one does not, so the
program terminates and the test fails without exercising the other
constructor variants.

This patch arranges to disable the test altogether when the
random_device feature is not available.  A reasonable alternative
would be to install a std::runtime_error handler around the test01
body, so that we exercise at least the exception raising, but then
test03 would have to be relaxed, since without even "default", it
likely wouldn't meet the tested requirement there.

Regstrapped on x86_64-linux-gnu and cross-tested for x86_64-vx7r2 along
with other patches, mostly for the testsuite.  Ok to install?


for  libstdc++-v3/ChangeLog

	* testsuite/26_numerics/random/random_device/cons/token.cc:
	Require effective target feature random_device.
---
 .../26_numerics/random/random_device/cons/token.cc |    1 +
 1 file changed, 1 insertion(+)

diff --git a/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc b/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
index defb8d58c586a..105ae0ba87743 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
@@ -1,4 +1,5 @@
 // { dg-do run { target c++11 } }
+// { dg-require-effective-target random_device }
 // { dg-require-cstdint "" }
 //
 // 2008-11-24  Edward M. Smith-Rowland <3dw4rd@verizon.net>


-- 
Alexandre Oliva, happy hacker  https://FSFLA.org/blogs/lxo/
   Free Software Activist         GNU Toolchain Engineer
        Vim, Vi, Voltei pro Emacs -- GNUlius Caesar