Experiment with minimized toolchain (2)

[alexey-milovidov]

Changelog category (leave one):

• Build/Testing/Packaging Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs).

Motivation:

• we will use custom sysroot even for default build;
• this will make our build reproducible: Make default build reproducible #22113;
• this will allow to fix libc blobs that are used during build: Fix compilation with glibc 2.34 (MINSIGSTKSZ defined as sysconf(_SC_SIGSTKSZ)) #29820, Add ability to compile using newer version fo glibc w/o using new symbols #29594;
• this will allow to add more platforms easily: Tasks on cross-compilation and platforms support #24371, Add CI check for PPC64le #25486, Add support for FreeBSD aarch64 #29952;
• this will allow enabling all libraries on ARM;

[alexey-milovidov]

We will be able to add protoc and llvm-tblgen there and enable more libraries.

[azat]

But where have you set CMAKE_TOOLCHAIN_FILE to this toolchain file?

[alexey-milovidov]

Currently in command line.

I've just tested that it works. I plan to also set it by default either in CMakeLists.txt on top or in PreLoad.cmake if the former is not possible.

[alexey-milovidov]

Special build check Ok.

Something strange with PVS-Studio...

[alexey-milovidov]

Fixed PVS-Studio.

[alexey-milovidov]

I've found how to build protoc for host system instead of target system during cross-compile.
It requires recursive invocation of cmake and it is done this way for llvm-tblgen.

[alexey-milovidov]

I've successfully built AArch64 binary with all the enabled libraries (LLVM, MySQL, Protobuf, GRPC, Parquet/ORC/Avro).

Most likely it's due to the fact that I have QEMU with binfmt-misc and AArch64 glibc installed,
and protoc works even compiled for target arch.

[alexey-milovidov]

Documentation: https://github.com/ClickHouse-Extras/sysroot/blob/master/README.md