core: pv - default number of buffer slots set to 40

- it was 10
- allow handling more chained evaluations in large strings

(cherry picked from commit c087b1d1dd06a1fd417998fe0a51dedcfe02e8c6)
(cherry picked from commit 352af1b5a878daf90e16f5ae012f5ecb87fabbff)

src/core/pvapi.c

@@ -1950,7 +1950,7 @@ static char **_pv_print_buffer = NULL;
 static int _pv_print_buffer_size  = PV_DEFAULT_PRINT_BUFFER_SIZE;
 static int _pv_print_buffer_size_active  = 0;
 /* 6 mod params + 4 direct usage from mods */
-#define PV_DEFAULT_PRINT_BUFFER_SLOTS 10
+#define PV_DEFAULT_PRINT_BUFFER_SLOTS 40
 static int _pv_print_buffer_slots = PV_DEFAULT_PRINT_BUFFER_SLOTS;
 static int _pv_print_buffer_slots_active = 0;
 static int _pv_print_buffer_index = 0;