Fix CMake compiler coroutine flags (#7404)

docs/CONTRIBUTORS

@@ -239,6 +239,7 @@ Sebastien Van Cauwenberghe
 Sergey Fedorov
 Sergi Granell
 Seth Pellegrino
+Shogo Yamazaki
 Shou-Li Hsu
 Srinivasan Venkataramanan
 Stefan Wallentowitz

verilator-config.cmake.in

@@ -743,15 +743,16 @@ function(verilate TARGET)
 
     target_link_libraries(${TARGET} PUBLIC ${VERILATOR_MT_CFLAGS})
 
-    target_compile_features(${TARGET} PRIVATE cxx_std_11)
-
     if(${VERILATE_PREFIX}_TIMING)
-        check_cxx_compiler_flag(-fcoroutines-ts COROUTINES_TS_FLAG)
-        target_compile_options(
-            ${TARGET}
-            PRIVATE
-                $<IF:$<BOOL:${COROUTINES_TS_FLAG}>,-fcoroutines-ts,-fcoroutines>
-        )
+        if("@CFG_CXXFLAGS_COROUTINES@" STREQUAL "-std=gnu++20")
+            target_compile_features(${TARGET} PRIVATE cxx_std_20)
+        else()
+            target_compile_options(
+                ${TARGET}
+                PRIVATE
+                    @CFG_CXXFLAGS_COROUTINES@
+            )
+        endif()
     endif()
 endfunction()