Pass VCPKG_LINKER_FLAGS_<CONFIG> from triplets to ports

[psfrolov]

Problem

Currently it is not possible to pass debug/release-specific linker flags to dynamic library builds. In practice I use release linker flags to fine-tune link-time optimisation with MSVC and Clang and debug linker flags to link with sanitiser runtimes.

Ports can use these flags via CMake built-in variables CMAKE_SHARED_LINKER_FLAGS_DEBUG and CMAKE_SHARED_LINKER_FLAGS_RELEASE. In fact, boost-modular-build for example already respects these variables while generating build config for b2). The only piece missing is to forward VCPKG_LINKER_FLAGS_RELEASE and VCPKG_LINKER_FLAGS_DEBUG variables from triplets to CMake.

Proposed solution

1. Forward the mentioned variables from triplet to project in scripts/cmake/vcpkg_configure_cmake.cmake
2. Setup appropriate CMake variables (e.g. CMAKE_SHARED_LINKER_FLAGS_DEBUG_INIT and CMAKE_SHARED_LINKER_FLAGS_RELEASE_INIT) in toolchain files (scripts/toolchains).

I use this approach in my Vcpkg fork, could make a PR.

[strega-nil]

Please make a PR, this sounds like a great feature :)

[JackBoosY]

Close this issue via #11290 merged.