In August VOLK changed an ifdef guard for complex.h that results in breaking builds for OOT modules when VOLK is installed because of some redefinitions. This has already broken and been fixed in a couple of OOT modules.
This is just a public heads up to anyone who might be maintaining a VOLK OOT module. To work with both pre v1.1.1 and post v1.1.1 you should do one of the following in your include/volk_<module_name>/volk_<module_name>_complex.h:
1) replace the current ifdef guard with
#if !defined(INCLUDED_VOLK_COMPLEX_H) && !defined(INCLUDE_VOLK_COMPLEX_H)
2) add the following ifdef guard to the existing one (do not replace to maintain backwards compatibility)
#ifndef INCLUDED_VOLK_COMPLEX_H
#define INCLUDED_VOLK_COMPLEX_H
And in both cases of course close off the guard at the end of the file.
-Nathan