Add description for _XOPEN_SOURCE_ - needed to allow autoheader to succeed.

diff --git a/configure.in b/configure.in
index 2d7b695fd629d24adca6aecd9264fe0806b03b23..3b593831013ee31f72b530c50faee3cc08ea8cca 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -20,7 +20,7 @@ VERSION=2.3
 AC_SUBST(SOVERSION)
 SOVERSION=1.0
 
-AC_DEFINE(_XOPEN_SOURCE, 500)
+AC_DEFINE(_XOPEN_SOURCE, 500, [Needed on Tru64 and does no harm on Linux])
 
 # Arguments passed to configure.
 AC_SUBST(CONFIG_ARGS)