chore: suppress warnings about unused llvm flags

Author: rioam2

wasi-sdk.toolchain.cmake

@@ -66,7 +66,14 @@ function(initialize_wasi_toolchain)
         WASI_SYSROOT_OUTPUT CMAKE_SYSROOT
         WASI_SDK_BIN_OUTPUT WASI_SDK_BIN
       )
-      string(APPEND CMAKE_CXX_FLAGS " -fwasm-exceptions -mllvm -wasm-use-legacy-eh=false -Wl,-lunwind")
+
+      # Add -mllvm flags without triggering unused argument warnings in older versions of clang that don't support them
+      string(APPEND CMAKE_CXX_FLAGS " --start-no-unused-arguments")
+      string(APPEND CMAKE_CXX_FLAGS " -mllvm -wasm-use-legacy-eh=false -Wl,-lunwind")
+      string(APPEND CMAKE_CXX_FLAGS " --end-no-unused-arguments")
+
+      # Link against libunwind for exception handling support.
+      string(APPEND CMAKE_CXX_FLAGS " -fwasm-exceptions")
       string(APPEND CMAKE_EXE_LINKER_FLAGS " -lunwind")
     else()
       include(${CMAKE_CURRENT_FUNCTION_LIST_DIR}/wasi-sdk.bootstrap.cmake)
@@ -123,9 +130,15 @@ function(initialize_wasi_toolchain)
     endif()
 
     if (arg_ENABLE_EXPERIMENTAL_SETJMP)
-      # Enable SJLJ support
+      # Add -mllvm flags without triggering unused argument warnings in older versions of clang that don't support them
+      string(APPEND CMAKE_C_FLAGS " --start-no-unused-arguments")
       string(APPEND CMAKE_C_FLAGS " -mllvm -wasm-enable-sjlj -mllvm -wasm-use-legacy-eh=false -Wl,-lsetjmp")
+      string(APPEND CMAKE_C_FLAGS " --end-no-unused-arguments")
+      string(APPEND CMAKE_CXX_FLAGS " --start-no-unused-arguments")
       string(APPEND CMAKE_CXX_FLAGS " -mllvm -wasm-enable-sjlj -mllvm -wasm-use-legacy-eh=false -Wl,-lsetjmp")
+      string(APPEND CMAKE_CXX_FLAGS " --end-no-unused-arguments")
+
+      # Link against setjmp library for setjmp/longjmp support.
       string(APPEND CMAKE_EXE_LINKER_FLAGS " -lsetjmp")
     endif()