- Add getexecpath() support for OpenBSD

Index: configure.cmake
--- configure.cmake.orig
+++ configure.cmake
@@ -342,6 +342,7 @@ CHECK_FUNCTION_EXISTS (fedisableexcept HAVE_FEDISABLEE
 CHECK_FUNCTION_EXISTS (fseeko HAVE_FSEEKO)
 CHECK_FUNCTION_EXISTS (fsync HAVE_FSYNC)
 CHECK_FUNCTION_EXISTS (getcwd HAVE_GETCWD)
+CHECK_FUNCTION_EXISTS (getexecpath HAVE_GETEXECPATH)
 CHECK_FUNCTION_EXISTS (gethostbyaddr_r HAVE_GETHOSTBYADDR_R)
 CHECK_FUNCTION_EXISTS (gethrtime HAVE_GETHRTIME)
 CHECK_FUNCTION_EXISTS (getpass HAVE_GETPASS)
