* Use `android-environment` instead of hardcoding paths
* Remove hacks for specifying include directories and standard
library manually
* Streamline compiler options with what CMake would use under
Android
* Use C++17
* Use an older glibc so resulting binaries can run
on older systems (without having to link statically
against glibc)
* Call packages static-compat-* to make it clear that
these packages are intended for compatibility with
older distributions
* Add further libraries to get static-compat-qt6-base
and some other static-compat-qt6-* packages building
sysroot and gcc-toolchain seem to be unneeded with toolchain with
platform versions in triplets.
Also unified the header search paths to use those headers from llvm
toolchain as much as possible.
This seems to fix the problem with dlopen refusing to load with "using
IE access model".