- Use of `rom_cordic_rotate` namespace to isolate functions and
variables. Useful when CORDICS are included in super project.
- Add define barrier to exclude some code when used when Xilinx v2019.1,
especially C++11/14 code that are not fully supported by the (crazy)
old version of GCC in use (v4.6.3).
Need the definition of `XILINX_MAJOR` (can be done using `set
XILINX_MAJOR [expr {int( [version -short] )}]` in a Xilinx TCL script
and then adding it to the cflags using the `-cflags` switch with
`-DXILINX_MAJOR=${XILINX_MAJOR}` or by manually adding the major
version to the CFLAGS in gui.
- Add a template version of the helper function, to support v2019.1.
