Implement futimes for Solaris using futimesat.

diff --git a/configure.ac b/configure.ac
index f6d908c..2b257d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1143,6 +1143,7 @@
 	fstatvfs \
 	ftruncate \
 	futimes \
+	futimesat \
 	getnetbyname \
 	getopt_long \
 	getpagesize \