Link with libexecinfo on OpenBSD for stacktrace functionality.

cmake/os/OpenBSD.cmake

@@ -0,0 +1,23 @@
+
+# Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1335  USA 
+
+# This file includes OpenBSD specific options and quirks, related to system checks
+
+# Find libexecinfo (library that contains backtrace_symbols etc)
+FIND_LIBRARY(EXECINFO NAMES execinfo)
+IF(EXECINFO)
+ SET(LIBEXECINFO ${EXECINFO})
+ENDIF()