Fix issue with INIT_WITH of array/list/....

combined with tuple:
_push_back_raw was used within an expanded macro
and as a consequence was expanded multiple times,
resulting in adding a new term in the sequence
for each field of the tuple.

m-core.h

@@ -3655,9 +3655,14 @@ m_core_parse2_enum (const char str[], const char **endptr)
 #define M_INIT_WITH_VAI22_FUNC(pair, a)                                       \
   M_INIT_WITH_VAI23_FUNC(M_PAIR_1 pair, M_PAIR_2 pair, a)
 
+/* We first push a raw new item, and then we get back its pointer using _back.
+  _back (contrary to _push_raw) has no side effect, and so is safe to be used
+  in a macro */  
 #define M_INIT_WITH_VAI23_FUNC(d, op, a)                                      \
-  M_IF(M_PARENTHESIS_P( a ))(M_CALL_INIT_WITH, M_CALL_INIT_SET)(M_GET_OPLIST op, *M_C( M_GET_NAME op , _push_raw)(d), M_REMOVE_PARENTHESIS (a))
-
+  (                                                                           \
+    (void) M_C(M_GET_NAME op, _push_raw)(d),                                  \
+    M_IF(M_PARENTHESIS_P( a ))(M_CALL_INIT_WITH, M_CALL_INIT_SET)(M_GET_OPLIST op, *M_C( M_GET_NAME op , _back)(d), M_REMOVE_PARENTHESIS (a)) \
+  )
 
 /* Initialize the container 'dest' as per 'oplist' INIT operator
    and fill it with the given VA argument

tests/test-malgo.c

@@ -26,6 +26,7 @@
 #include "m-string.h"
 #include "m-deque.h"
 #include "m-dict.h"
+#include "m-tuple.h"
 #include "m-algo.h"
 
 #include "test-obj.h"
@@ -51,6 +52,11 @@ DICT_DEF2(dict_int, string_t, int)
 ARRAY_DEF(array_uint, unsigned int)
 #define M_OPL_array_uint_t() ARRAY_OPLIST(array_uint)
 
+TUPLE_DEF2(person, (age, int), (name, string_t) )
+#define M_OPL_person_t() TUPLE_OPLIST(person, M_DEFAULT_OPLIST, STRING_OPLIST)
+ARRAY_DEF(array_person, person_t)
+#define M_OPL_array_person_t() ARRAY_OPLIST(array_person, M_OPL_person_t() )
+
 #include "coverage.h"
 START_COVERAGE
 ALGO_DEF(algo_array, array_int_t)
@@ -493,6 +499,14 @@ static void test_string(void)
   string_clear(s);
   
   list_string_clear(l);
+
+  M_LET( (a, (13, ("Jean") ),(14, ("Michael"))), array_person_t ) {
+    assert( array_person_size(a) == 2);
+    assert( (*array_person_get(a, 0))->age == 13 );
+    assert( string_equal_str_p( (*array_person_get(a, 0))->name, "Jean") );
+    assert( (*array_person_get(a, 1))->age == 14 );
+    assert( string_equal_str_p( (*array_person_get(a, 1))->name, "Michael") );
+  }
 }
 
 static void test_extract(void)