Improve consistency with different compilers about cmsis-dsp HOT 3 CLOSED

@petertorelli You can just define __GNUC_PYTHON__.
The name of the define is not very clear. It was initially introduced for building the Python wrapper but now it is generally used to build for host.

I don't want to have automatic detection like with __GNUC__ because if you compile with gcc and target Arm you will want some DSP instructions existing on Cortex-A aarch32.

The meaning of __GNUC_PYTHON__ is to disable those DSP extensions and use instead pure C implementation.

In fact, what I am trying to detect is not the compiler but the host platform. So when it is built with MSVC or XCode I can detect the platform from the compiler. When it is built with gcc or clang I can't. So the developer just has to define __GNUC_PYTHON__

from cmsis-dsp.

I'll generate a PR if this is a legit issue.

from cmsis-dsp.

I understand now, thanks. (I've tried to determine platform architecture from predefined compiler macros before and it was maddening due to utter lack of standardization.)

from cmsis-dsp.