gcc/ChangeLog:
* doc/install.texi (Configuration): Switch valgrind.com to https.
therefore not differ between stage1 and later stages in bootstrap.
The @samp{valgrind} check requires the external @command{valgrind} simulator,
-available from @uref{http://valgrind.org/}. The @samp{rtl} checks are
+available from @uref{https://valgrind.org}. The @samp{rtl} checks are
expensive and the @samp{df}, @samp{gcac} and @samp{valgrind} checks are very
expensive.