Remove -static and rename static build appropriately.

[fruffy]

Turns out we can not really build a clean static binary on Linux because of limitations of the glibc library.

https://stackoverflow.com/questions/3430400/linux-static-linking-is-dead

Also, linking with -static causes problems when building Protobuf and bdwgc from scratch. Hence, we remove -static from our build process and rename the CMake parameters appropriately.

[vlstill]

@fruffy, what is the status of this? The changes look reasonable to me, but it is still marked WIP.

[vlstill]

There is a way to build fully static binaries on Linux. It basically requires using different libc implementation than glibc as glibc will do dlopen for some features even if build statically and therefore it is never fully static (SO thread). One option that I have seen successfully used in using the Alpine Linux that uses musl libc. I can even try making that work for p4c if desirable. But there is a counter-argument to that and that is that linking libc statically moves the critical compatibility interface from glibc, which is widely used and attempts to be forward-compatible to Linux kernel interface, which does not need to be so stable. I'm not sure how much concern this actually is as I don't have enough knowledge about Linux kernel interlace.

For most uses it should be sufficient to use static-sans-glibc and to build on a distro with the oldest glibc that can possibly be used. Note that using musl instead of glibc will likely bring some performance differences (and a small potential for different bugs).

[fruffy]

@fruffy, what is the status of this? The changes look reasonable to me, but it is still marked WIP.

I was thinking about a solution similar to what you described in your comment. And I also need to implement the CI check. It is a little finicky since we need to grep for a lack of specific libraries.

[vlstill]

I was thinking about a solution similar to what you described in your comment.

I still think the static-sans-glibc is actually a more useful build type. There would be niche cases where fully-static would be desired, but that would basically require validating the whole compiler in that mode quite thoroughly.

[vlstill]

Just one comment. Otherwise, I agree with this. It should probably be also reviewed by someone of the core p4c like @mihaibudiu.

[vlstill]

It would still make sense to include the previous value of CMAKE_EXE_LINKER_FLAGS I think. The user should have ability to add to them.