Do not try to compile Python code when building other bindings

Fixes the issue reported by @dl8fcl
f7d38f92ca (commitcomment-161078321)

bindings/amplifier.swg

@@ -148,6 +148,7 @@ typedef struct Amp {
 
   AMPMETHOD1GET(get_powerstat, powerstat_t)
 
+#ifdef SWIGPYTHON
   PyObject * get_level(setting_t level)
   {
       value_t val;
@@ -163,5 +164,5 @@ typedef struct Amp {
 
       return PyLong_FromLong(val.i);
   }
-
+#endif
 };

bindings/rotator.swg

@@ -119,6 +119,7 @@ typedef struct Rot {
 
 	ROTMETHOD2(set_conf, hamlib_token_t, const_char_string)
 
+#ifdef SWIGPYTHON
 	ROT_GET_LONG(func)
 	ROT_GET_LONG(ext_func)
 
@@ -127,6 +128,7 @@ typedef struct Rot {
 
 	ROT_GET_VALUE_T(parm)
 	ROT_GET_VALUE_T(ext_parm)
+#endif
 
         const char *get_conf(hamlib_token_t tok) {
                 static char s[128] = "";