Improve configure check for log2
commit74f31bb87b4b1a4dcc9ba00401e808612f65325a
authorOlly Betts <olly@survex.com>
Sat, 17 Dec 2016 07:13:23 +0000 (17 20:13 +1300)
committerOlly Betts <olly@survex.com>
Mon, 19 Dec 2016 00:42:01 +0000 (19 13:42 +1300)
tree3f00b867aad9b1b76c33dd0172755ed1165c5be6
parent2f290ee0336537e66ddccc216fd88e5762129c62
Improve configure check for log2

We include <cmath> so the check really needs to work if only std::log2()
is declared.

(cherry picked from commit dc9c9ce72957a4b9642075b8470a56807e721254)
xapian-core/configure.ac