Add async message port to switch muting on and off.
Add message port to XML file for GRC.
volk: potentially better solution to finding the architecture for ASM files.

OE bitbake environment and the SDK cross-compiling environments put the -march flag in different places. This pulls both together to search for it. Might still be a better solution out there.
volk: adding arm_neon.h headers to remaining neon proto-kernels.
Merge branch 'master' into next
uhd: fixed tagged stream block gap handling in usrp_sink
Merge branch 'maint'

Conflicts:
	gr-uhd/lib/usrp_sink_impl.cc
Merge branch 'master' into next
Merge remote-tracking branch 'argilo/mute-changes'
Merge branch 'master' into next
blocks: fix subtract_ff
blocks: fixes qa code to test more sub_XX cases.
Merge branch 'master' into next
controlport: removing use of ice for a controlport rpc.

This effectively disables the use of ControlPort for now until we build in a new middleware layer. The ControlPort API and interfaces exist but will function as nops for now.
Merge branch 'maint'

Conflicts:
	gnuradio-runtime/CMakeLists.txt
	gnuradio-runtime/lib/controlport/CMakeLists.txt
cmake: follow-up to previous merge
Merge branch 'master' into next
modtool: removing RTLD_GLOBAL hack for swig in gr-modtool.

This was removed from GNU Radio a while ago due to newer issues. Looks like it's affecting OOT modules as well.
volk: add check for posix_memalign for OSs that do not directly set _XOPEN_SOURCE or _POSIX_C_SOURCE; define and use the new variable when found.
logger: adding new configure_default_logger function to make it easier to get log file info on logger setup.