src/output: Unconst-cast tputs

Fixes the build on Solaris/OpenIndiana/Illumos.

src/output.cpp

@@ -357,7 +357,9 @@ int outputter_t::term_puts(const char *str, int affcnt) {
     // scoped_push will restore it.
     scoped_lock locker{s_tputs_receiver_lock};
     scoped_push<outputter_t *> push(&s_tputs_receiver, this);
-    return tputs(str, affcnt, tputs_writer);
+    // On some systems, tputs takes a char*, on others a const char*.
+    // Like tparm, we just cast it to unconst, that should work everywhere.
+    return tputs((char *)str, affcnt, tputs_writer);
 }
 
 /// Write a wide character to the outputter. This should only be used when writing characters from