configure: Disable rpass-valgrind when there's no valgrind#24859

Merged

bors merged 4 commits intorust-lang:masterfrom richo:valgrind-tests

May 9, 2015

+23-6

Commits on Apr 27, 2015

Commits on Apr 28, 2015

configure: Fail iff valgrind is explicitly requested but not available
richo
committed

Commits on May 8, 2015

mk: Log that valgrind tests are disabled
richo
committed