sanitizer libs in ctng-compilers have wrong pinning

[nehaljwani]

Take the example of let's say: libasan . On each compiler major bump, it bumps it's soname, making it incompatible with older versions. Right now, if I build a conda package with -fsanitize=address and gcc 7.3.0 and by run_exports I get a dependency of libgcc-ng >=7.3.0 and libstdcxx-ng >=7.3.0 which, on installation, will bring in latest versions of libgcc-ng and libstdcxx-ng, thereby breaking my package.

One solution could be to split the sanitizer libs into a separate conda package and restrict it's pinning.