Create our own shared library

There's a pretty nasty bug where Cargo can't generate the shared library
itself, and we need to do in CMake. This isn't a huge deal, as we can
simply link to the static library created by Cargo.

This is an upstream issue where Rust marks unknown symbols as local, and
they never appear in the dynamic symbol table. There is an open issue
to allow more granular filtering
(rust-lang/rust#104130) as well as an upstream
CXX issue (dtolnay/cxx#1331)

CMakeLists.txt

@@ -1,16 +1,18 @@
+# 3.24 is needed for LINK_LIBRARY:WHOLE_ARCHIVE support
 cmake_minimum_required(VERSION 3.24)
 
-project(Vodozemac-cpp)
+project(vodozemac-cpp)
 
 find_package(Corrosion REQUIRED)
 
 corrosion_import_crate(
     MANIFEST_PATH Cargo.toml
 )
 
-add_custom_target(copy_header ALL DEPENDS cargo-build_vodozemac BYPRODUCTS ${CMAKE_BINARY_DIR}/vodozemac.h VERBATIM COMMAND
-    cp -L ${CMAKE_BINARY_DIR}/cargo/build/${Rust_CARGO_TARGET}/cxxbridge/vodozemac/src/lib.rs.h ${CMAKE_BINARY_DIR}/vodozemac.h
-)
-
-corrosion_install(TARGETS vodozemac)
-install(FILES "${CMAKE_BINARY_DIR}/vodozemac.h" DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/vodozemac)
+# We create our own shared library instead of having Cargo do it
+# To work around https://github.com/dtolnay/cxx/issues/1331
+add_library(vodozemac-cpp SHARED)
+# We need a dummy file so CMake will have something to link with
+target_sources(vodozemac-cpp PRIVATE src/dummy.cpp)
+# We need to link to the whole archive, otherwise important symbols are thrown away
+target_link_libraries(vodozemac-cpp PRIVATE "$<LINK_LIBRARY:WHOLE_ARCHIVE,vodozemac-static>")

src/dummy.cpp

@@ -0,0 +1 @@
+// This file is intentionally left blank