Userland+Tests: Add initial riscv64 support

Author: https://github.com/spholz
Commit: 6824d2a788
Pull-request: https://github.com/SerenityOS/serenity/pull/21139
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Userland/Libraries/LibDebug/DebugSession.h

@@ -193,6 +193,9 @@ void DebugSession::run(DesiredInitialDebugeeState initial_debugee_state, Callbac
 #elif ARCH(AARCH64)
         FlatPtr current_instruction;
         TODO_AARCH64();
+#elif ARCH(RISCV64)
+        FlatPtr current_instruction;
+        TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif
@@ -217,6 +220,9 @@ void DebugSession::run(DesiredInitialDebugeeState initial_debugee_state, Callbac
 #elif ARCH(AARCH64)
                 FlatPtr current_ebp;
                 TODO_AARCH64();
+#elif ARCH(RISCV64)
+                FlatPtr current_ebp;
+                TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif
@@ -266,6 +272,9 @@ void DebugSession::run(DesiredInitialDebugeeState initial_debugee_state, Callbac
 #elif ARCH(AARCH64)
             (void)breakpoint_addr;
             TODO_AARCH64();
+#elif ARCH(RISCV64)
+            (void)breakpoint_addr;
+            TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif