fix: use custom protoc command for cross-platform compatibility

- Replace protobuf_generate with custom add_custom_command
- Use --proto_path to ensure correct symbol naming
- Linux/macOS use system protobuf (apt/brew)
- Windows uses vcpkg
- Update documentation for platform-specific dependencies

Author: Sqhh99

CMakeLists.txt

@@ -76,7 +76,11 @@ set(FFI_PROTO_FILES
 set(PROTO_BINARY_DIR ${LIVEKIT_BINARY_DIR}/generated)
 file(MAKE_DIRECTORY ${PROTO_BINARY_DIR})
 
-find_package(Protobuf CONFIG REQUIRED)
+# Try to find Protobuf via CONFIG mode first (vcpkg), then fall back to MODULE mode (apt/brew)
+find_package(Protobuf CONFIG QUIET)
+if(NOT Protobuf_FOUND)
+  find_package(Protobuf REQUIRED)
+endif()
 
 add_library(livekit_proto OBJECT ${FFI_PROTO_FILES})
 target_include_directories(livekit_proto PRIVATE
@@ -85,13 +89,28 @@ target_include_directories(livekit_proto PRIVATE
 )
 target_link_libraries(livekit_proto PRIVATE protobuf::libprotobuf)
 
-protobuf_generate(
-  LANGUAGE cpp
-  TARGET livekit_proto
-  PROTOC_OUT_DIR ${PROTO_BINARY_DIR}
-  IMPORT_DIRS ${FFI_PROTO_DIR}
+# Manually generate protobuf files to avoid path prefix issues
+set(PROTO_SRCS)
+set(PROTO_HDRS)
+foreach(PROTO_FILE ${FFI_PROTO_FILES})
+  get_filename_component(PROTO_NAME ${PROTO_FILE} NAME_WE)
+  list(APPEND PROTO_SRCS "${PROTO_BINARY_DIR}/${PROTO_NAME}.pb.cc")
+  list(APPEND PROTO_HDRS "${PROTO_BINARY_DIR}/${PROTO_NAME}.pb.h")
+endforeach()
+
+add_custom_command(
+  OUTPUT ${PROTO_SRCS} ${PROTO_HDRS}
+  COMMAND ${Protobuf_PROTOC_EXECUTABLE}
+    --proto_path=${FFI_PROTO_DIR}
+    --cpp_out=${PROTO_BINARY_DIR}
+    ${FFI_PROTO_FILES}
+  DEPENDS ${FFI_PROTO_FILES}
+  COMMENT "Generating C++ protobuf files"
+  VERBATIM
 )
 
+target_sources(livekit_proto PRIVATE ${PROTO_SRCS} ${PROTO_HDRS})
+
 set(GENERATED_INCLUDE_DIR "${LIVEKIT_BINARY_DIR}/generated")
 file(MAKE_DIRECTORY "${GENERATED_INCLUDE_DIR}")
 

DEPENDENCIES.md

@@ -140,27 +140,26 @@ sudo dnf install protobuf-devel abseil-cpp-devel openssl-devel
 
 ```cmake
 find_package(Protobuf REQUIRED)
-find_package(absl REQUIRED)
 find_package(OpenSSL REQUIRED)
 
 target_link_libraries(your_app PRIVATE
     # LiveKit static libraries
     livekit
     livekit_ffi
     
-    # Protobuf and Abseil (REQUIRED)
+    # Protobuf (REQUIRED)
     protobuf::libprotobuf
-    absl::log
-    absl::check
-    absl::strings
-    absl::base
     
     # Linux system libraries (REQUIRED)
     OpenSSL::SSL
     OpenSSL::Crypto
     pthread
     dl
 )
+
+# NOTE: If using Protobuf 6.0+, you also need to link Abseil:
+# find_package(absl REQUIRED)
+# target_link_libraries(your_app PRIVATE absl::log absl::strings absl::base)
 ```
 
 ### Manual Linking (Makefile/gcc)
@@ -169,8 +168,7 @@ g++ your_app.cpp \
     -I/path/to/livekit/include \
     -L/path/to/livekit/lib \
     -llivekit -llivekit_ffi \
-    -lprotobuf -labsl_log -labsl_strings -labsl_base \
-    -lssl -lcrypto -lpthread -ldl
+    -lprotobuf -lssl -lcrypto -lpthread -ldl
 ```
 
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