CxxFlutterSwift: explicitly linkedLibrary backend C libs#21
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The .systemLibrary(pkgConfig: ...) targets (CGBM, CEGL, CXKBCommon, CLibDRM, CLibInput, CLibUDev, and the wayland-cursor/wayland-egl pair) provide pkg-config-driven cflags that compile cleanly, but SwiftPM doesn't always propagate their pkg-config --libs through a C++ intermediate target (CxxFlutterSwift) to the final executable link. The symptom, seen on cross-builds where pkg-config otherwise works, is ld.lld: undefined symbol: gbm_create_device / eglChooseConfig / xkb_keymap_mod_get_index / ... even though the headers were found. Add an explicit .linkedLibrary list on CxxFlutterSwift, keyed off the same FlutterELinuxBackend switch that drives BackendDependencies, so the final executable is guaranteed to pick up the backend's C libs. The .systemLibrary + pkgConfig plumbing is kept as-is for the -I/-D side and for environments where SwiftPM does propagate --libs through. Verified: FLUTTER_SWIFT_BACKEND=gbm swift build links counter cleanly, and the resulting binary's NEEDED list contains libgbm.so.1, libEGL.so.1, libGLESv2.so.2, libdrm.so.2, libinput.so.10, libudev.so.1, libxkbcommon.so.0. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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The .systemLibrary(pkgConfig: ...) targets (CGBM, CEGL, CXKBCommon, CLibDRM, CLibInput, CLibUDev, and the wayland-cursor/wayland-egl pair) provide pkg-config-driven cflags that compile cleanly, but SwiftPM doesn't always propagate their pkg-config --libs through a C++ intermediate target (CxxFlutterSwift) to the final executable link. The symptom, seen on cross-builds where pkg-config otherwise works, is ld.lld: undefined symbol: gbm_create_device / eglChooseConfig / xkb_keymap_mod_get_index / ... even though the headers were found.
Add an explicit .linkedLibrary list on CxxFlutterSwift, keyed off the same FlutterELinuxBackend switch that drives BackendDependencies, so the final executable is guaranteed to pick up the backend's C libs. The .systemLibrary + pkgConfig plumbing is kept as-is for the -I/-D side and for environments where SwiftPM does propagate --libs through.
Verified: FLUTTER_SWIFT_BACKEND=gbm swift build links counter cleanly, and the resulting binary's NEEDED list contains libgbm.so.1, libEGL.so.1, libGLESv2.so.2, libdrm.so.2, libinput.so.10, libudev.so.1, libxkbcommon.so.0.