Improve configure check for log2
commitdc9c9ce72957a4b9642075b8470a56807e721254
authorOlly Betts <olly@survex.com>
Sat, 17 Dec 2016 07:13:23 +0000 (17 20:13 +1300)
committerOlly Betts <olly@survex.com>
Sat, 17 Dec 2016 07:13:23 +0000 (17 20:13 +1300)
treeef58af6e5515648623d45f231e72e403714a2f64
parentc8dca7c786a1feab94cb0ee609c4b809ef40d52d
Improve configure check for log2

We include <cmath> so the check really needs to work if only std::log2()
is declared.
xapian-core/configure.ac