[native] Better p/invoke handling when loading foreign libraries

[grendello]

Improve looking for "foreign" libraries when resolving a p/invoke symbol.

Foreign libraries are those which either aren't contained in the application APK
or which reside on the device in a system location. In such cases, we must attempt
to load the library using its name passed from the managed code (which uses the
DllImport attribute to name the library).

Since DllImport doesn't usually use full name of the target library (e.g. instead
of liblog.so it will use either liblog or log), we must modify the library
name so that the dlopen(3) call can find it on the filesystem. We must make sure
that the library name follows the libNAME.so convention before attempting to load
the library from filesystem..

This is an interim fix for us not finding e.g. the liblog.so library when the
[DllImport("liblog")] attribute is used in the managed code. The library resolution
and reloading system must be redesigned, which will happen in a separate PR as it is
currently not the highest priority task.

[Copilot]

Pull Request Overview

This PR improves the handling of foreign libraries loaded via p/invoke by ensuring that library names match the expected system naming conventions. Key changes include:

• Adding an ends_with() utility function to check string suffixes in the runtime-base strings utilities.
• Simplifying the library path resolution logic in AndroidSystem and updating DSO loading via a templated monodroid_dlopen.
• Introducing a new constant DSO_PREFIX and a utility function to detect directory components in paths.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/native/common/include/runtime-base/strings.hh	Added an ends_with() helper for string suffix checking.
src/native/clr/runtime-base/android-system.cc	Refactored library path resolution and suffix handling.
src/native/clr/include/runtime-base/util.hh	Added a utility to check for directory separators in paths.
src/native/clr/include/runtime-base/monodroid-dl.hh	Updated monodroid_dlopen to a templated version using a flag.
src/native/clr/include/host/pinvoke-override.hh	Adjusted p/invoke override to use the new templated API.
src/native/clr/include/constants.hh	Introduced DSO_PREFIX for consistent library name handling.

Comments suppressed due to low confidence (1)

src/native/clr/include/runtime-base/monodroid-dl.hh:109

• [nitpick] Consider adding a clarifying comment explaining the purpose and expected usage of the template parameter PREFER_AOT_CACHE to aid future maintainers in understanding this API change.

template<bool PREFER_AOT_CACHE> [[gnu::flatten]]

[jonathanpeppers]

Just for me to understand, length() is always inlined, so no problem with calling it multiple times in an expression?

android/src/native/common/include/runtime-base/strings.hh

Lines 452 to 453 in 2ef0038

	[[gnu::always_inline]]
	auto length () const noexcept -> size_t

[grendello]

Yeah, it's fully inlined each time it's called (which can also the be further optimized by common sub-expression elimination and other techniques, depending on context)