[tracker] libtracker-data: Define constraint values for older SQLite versions

[Carlos Garnacho <carlosg src gnome org>]

commit d931d7dd70a1a8127c9bfea03d7d8931f7af988d
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Feb 6 10:06:37 2019 +0100

    libtracker-data: Define constraint values for older SQLite versions
    
    These were added in sqlite 3.21.0. For the places where updating
    SQLite is not easy/possible, just define those. Presumably older
    SQLite versions will fall back through other operators in the
    xBestIndex method, either way we won't get those from the DB engine.

 src/libtracker-data/tracker-vtab-triples.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/src/libtracker-data/tracker-vtab-triples.c b/src/libtracker-data/tracker-vtab-triples.c
index 9ff15b628..92a5ff86c 100644
--- a/src/libtracker-data/tracker-vtab-triples.c
+++ b/src/libtracker-data/tracker-vtab-triples.c
@@ -22,6 +22,15 @@
 
 #include "tracker-vtab-triples.h"
 
+/* Define some constraints for older SQLite, we will never get
+ * those in older versions, and simplifies checks in code.
+ */
+#if SQLITE_VERSION_NUMBER<=3021000
+#define SQLITE_INDEX_CONSTRAINT_NE        68
+#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
+#define SQLITE_INDEX_CONSTRAINT_ISNULL    71
+#endif
+
 enum {
        COL_ROWID,
        COL_GRAPH,