While the license subject has been brought up, would appreciate any clarification on how licenses/copyrights might apply to runtime libraries like musl and distributing executables. 

Here's what I've dug up trying to read through the 'legalese'.  gcc provides a runtime exception ( http://www.gnu.org/licenses/gcc-exception-faq.html ), so according to it, you should be able to use the license of your choice with your executable and don't have to use the compiler's license.  Linux kernel developers don't consider the API an issue and have a note ( https://www.kernel.org/pub/linux/kernel/COPYING ) about not copyrighting kernel services through normal system calls.  Zvi and I were discussing copyright and he mentioned the case of Oracle against Google and that APIs were found not copyrightable.  So, if you build a program with gcc and musl as the runtime library, do you need to distribute any kind of licensing information other than whatever you decide to license your own program under?

I was reading some information on mingw-w64.  It uses a runtime made up of a variety of licenses (from BSD to LGPL). 
There's mention of distributing a runtime license with executables created by the compiler:
http://www.math.washington.edu/tex-archive/systems/texlive/tlnet/tlpkg/installer/COPYING.MinGW-runtime.txt
With mingw (the original from www.mingw.org), the runtime has always been in the public domain in the past, so needing to supply the end user with a runtime license when distributing executables was never necessary.  Was surprised to read the recommendation that one needed a runtime license to distribute programs with mingw-w64.  My understanding was that one doesn't need this sort of thing for gcc/glibc on standard Linux systems.  I'm wondering what applies to musl and what doesn't.  Does one need to distribute the musl license when distributing executables built with it?  Does the gcc compiler runtime exception cover the issue or is there something else that applies?  Also can't help wondering how it applies to llvm (http://llvm.org/docs/DeveloperPolicy.html#license) and executables built with it.

I agree with the previous comment posted about the more licenses involved the more confusing it can get.  Any further information or clarifications would be greatly appreciated.  Thanks.

Sincerely,
Laura