grc: python 2.6 compatibility fix
uhd: fixed tagged stream block gap handling in usrp_sink
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.
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.
modtool: Fixed a bug in makexml for int-type io signatures
volk: simplifies and fixes thread safety issue in volk_malloc/free.
blocks: delay block cannot be initialized with a negative number.

This commit puts in a check in the constructor and better
documentation about the behavior.
Merge remote-tracking branch 'martin/modtool/bugfix' into maint
Fix for #647 - GUI Tabs do not switch on WX GUI Scope sink channels on OSX

With this patch, the bug is not showing anymore. It was only tested by
me on Mac OS X - not on Linux nor other platforms.
The possible regressions introduced by fix should be limited to the
notebook chooser forms only.
Merge remote-tracking branch 'gnuradio-wg-grc/grc_py26_compat_fix' into maint
cmake: backport parallel build fix to maint branch
cmake: add parallel build fix to gr_modtool template
digital: fix mask of correlate access code tag

basically reverts ba2951861b99f59df79022f98f51a12273fe2aa8
digital: correlate access code uses MSB