bug#51431: faust 2.5.23 fails to build

[Thorsten Wilms]

First, during patch-shebang, it warns about missing python, pure and
ruby.

Then:

```
httpd/HTTPDServer.cpp: In member function ‘bool 
httpdfaust::HTTPDServer::start(int)’:
httpd/HTTPDServer.cpp:118:118: error: invalid conversion from ‘int (*)(void*, 
MHD_Connection*, const char*, const char*, const char*, const char*, size_t*, 
void**) {aka int (*)(void*, MHD_Connection*, const char*, const char*, const 
char*, const char*, long unsigned int*, void**)}’ to ‘MHD_AccessHandlerCallback 
{aka MHD_Result (*)(void*, MHD_Connection*, const char*, const char*, const 
char*, const char*, long unsigned int*, void**)}’ [-fpermissive]
  fServer = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY, port, NULL, NULL, 
_answer_to_connection, this, MHD_OPTION_END);
                                                                                
                                      ^
In file included from httpd/HTTPDServer.h:52:0,
                 from httpd/HTTPDServer.cpp:32:
/gnu/store/wqqh2qj4ahday9qqrs5axhbvy4qkpzx7-libmicrohttpd-0.9.73/include/microhttpd.h:2477:1:
 note:   initializing argument 5 of ‘MHD_Daemon* MHD_start_daemon(unsigned int, 
uint16_t, MHD_AcceptPolicyCallback, void*, MHD_AccessHandlerCallback, void*, 
...)’
 MHD_start_daemon (unsigned int flags,
 ^~~~~~~~~~~~~~~~
httpd/HTTPDServer.cpp: In member function ‘int 
httpdfaust::HTTPDServer::answer(MHD_Connection*, const char*, const char*, 
const char*, const char*, size_t*, void**)’:
httpd/HTTPDServer.cpp:224:61: error: invalid conversion from ‘int (*)(void*, 
MHD_ValueKind, const char*, const char*)’ to ‘MHD_KeyValueIterator {aka 
MHD_Result (*)(void*, MHD_ValueKind, const char*, const char*)}’ [-fpermissive]
  MHD_get_connection_values (connection, t, _get_params, &msg);
                                                             ^
In file included from httpd/HTTPDServer.h:52:0,
                 from httpd/HTTPDServer.cpp:32:
/gnu/store/wqqh2qj4ahday9qqrs5axhbvy4qkpzx7-libmicrohttpd-0.9.73/include/microhttpd.h:2782:1:
 note:   initializing argument 3 of ‘int 
MHD_get_connection_values(MHD_Connection*, MHD_ValueKind, MHD_KeyValueIterator, 
void*)’
 MHD_get_connection_values (struct MHD_Connection *connection,
 ^~~~~~~~~~~~~~~~~~~~~~~~~
make[1]: *** [<builtin>: httpd/HTTPDServer.o] Error 1
```

It continues to do stuff with a whole bunch of warnings,
to finally end with:

```
command "make" "-j" "8" 
"prefix=/gnu/store/h1mxkm7cvm920bcki8q83zmcf7ljmkjf-faust-2.5.23" "world" 
failed with status 2
```