diff --git a/changes/bug17819 b/changes/bug17819
new file mode 100644
index 0000000000..45c55f74b6
--- /dev/null
+++ b/changes/bug17819
@@ -0,0 +1,4 @@
+  o Minor bugfixes (compilation):
+    - Don't try to use the pthrad_condattr_setclock() function unless
+      it actually exists.  Fixes compilation on NetBSD-6.x. Fixes bug
+      17819; bugfix on 0.2.6.3-alpha.
diff --git a/configure.ac b/configure.ac
index c723257ea3..25edbaf1d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -422,6 +422,7 @@ AC_CHECK_FUNCS(
 if test "$bwin32" != true; then
   AC_CHECK_HEADERS(pthread.h)
   AC_CHECK_FUNCS(pthread_create)
+  AC_CHECK_FUNCS(pthread_condattr_setclock)
 fi
 
 if test "$bwin32" = true; then
diff --git a/src/common/compat_pthreads.c b/src/common/compat_pthreads.c
index 4b32fc93d2..b1d87d38f2 100644
--- a/src/common/compat_pthreads.c
+++ b/src/common/compat_pthreads.c
@@ -185,7 +185,8 @@ tor_cond_init(tor_cond_t *cond)
     return -1;
   }
 
-#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
+#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC) \
+  && defined(HAVE_PTHREAD_CONDATTR_SETCLOCK)
   /* Use monotonic time so when we timedwait() on it, any clock adjustment
    * won't affect the timeout value. */
   if (pthread_condattr_setclock(&condattr, CLOCK_MONOTONIC)) {