HackStudio: Enable building HackStudio on x86_64

This implements bits and pieces to get the debugging functionality to
build. No testing has been done to check whether it actually works
because GCC doesn't currently work.

Userland/Libraries/LibC/sys/arch/i386/regs.h

@@ -46,4 +46,42 @@ struct [[gnu::packed]] PtraceRegisters {
     u32 es;
     u32 fs;
     u32 gs;
+
+#ifdef __cplusplus
+    FlatPtr ip() const
+    {
+#    if ARCH(I386)
+        return eip;
+#    else
+        return rip;
+#    endif
+    }
+
+    void set_ip(FlatPtr ip)
+    {
+#    if ARCH(I386)
+        eip = ip;
+#    else
+        rip = ip;
+#    endif
+    }
+
+    FlatPtr bp() const
+    {
+#    if ARCH(I386)
+        return ebp;
+#    else
+        return rbp;
+#    endif
+    }
+
+    void set_bp(FlatPtr bp)
+    {
+#    if ARCH(I386)
+        ebp = bp;
+#    else
+        rbp = bp;
+#    endif
+    }
+#endif
 };