[embedded][Concurrency] Build C++ runtime Concurrency code with -ffunction-sections and more embedded friendly flags

Author: kubamracek

stdlib/public/Concurrency/CMakeLists.txt

@@ -316,6 +316,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
         ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS}
       C_COMPILE_FLAGS
         ${extra_c_compile_flags} ${SWIFT_RUNTIME_CONCURRENCY_C_FLAGS} -DSWIFT_CONCURRENCY_EMBEDDED=1 -DSWIFT_RUNTIME_EMBEDDED=1
+        -ffunction-sections -fdata-sections -fno-exceptions -fno-cxx-exceptions -fno-unwind-tables
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
       ARCHITECTURE "${mod}"