Suppress remaining -Waddress warnings from recent gcc versions.

Still an exercise in satisfying pedants.

src/bin/psql/psqlscan.l

@@ -1673,7 +1673,7 @@ evaluate_backtick(void)
 		error = true;
 	}
 
-	if (PQExpBufferBroken(&cmd_output))
+	if (PQExpBufferDataBroken(cmd_output))
 	{
 		psql_error("%s: out of memory\n", cmd);
 		error = true;

src/interfaces/libpq/fe-connect.c

@@ -829,7 +829,7 @@ PQconndefaults(void)
 	PQconninfoOption *connOptions;
 
 	initPQExpBuffer(&errorBuf);
-	if (PQExpBufferBroken(&errorBuf))
+	if (PQExpBufferDataBroken(errorBuf))
 		return NULL;			/* out of memory already :-( */
 	connOptions = conninfo_parse("", &errorBuf, true);
 	termPQExpBuffer(&errorBuf);
@@ -3967,7 +3967,7 @@ PQconninfoParse(const char *conninfo, char **errmsg)
 	if (errmsg)
 		*errmsg = NULL;			/* default */
 	initPQExpBuffer(&errorBuf);
-	if (PQExpBufferBroken(&errorBuf))
+	if (PQExpBufferDataBroken(errorBuf))
 		return NULL;			/* out of memory already :-( */
 	connOptions = conninfo_parse(conninfo, &errorBuf, false);
 	if (connOptions == NULL && errmsg)

src/interfaces/libpq/pqexpbuffer.h

@@ -59,6 +59,14 @@ typedef PQExpBufferData *PQExpBuffer;
 #define PQExpBufferBroken(str)	\
 	((str) == NULL || (str)->maxlen == 0)
 
+/*------------------------
+ * Same, but for use when using a static or local PQExpBufferData struct.
+ * For that, a null-pointer test is useless and may draw compiler warnings.
+ *------------------------
+ */
+#define PQExpBufferDataBroken(buf)	\
+	((buf).maxlen == 0)
+
 /*------------------------
  * Initial size of the data buffer in a PQExpBuffer.
  * NB: this must be large enough to hold error messages that might