Get SQLite to build

* changed headers
* removed redundant declarations
* ran clang-format
* added sqlite3.mk

third_party/sqlite3/mem0.c

@@ -16,7 +16,8 @@
 ** are merely placeholders.  Real drivers must be substituted using
 ** sqlite3_config() before SQLite will operate.
 */
-#include "sqliteInt.h"
+#include "third_party/sqlite3/sqliteInt.h"
+/* clang-format off */
 
 /*
 ** This version of the memory allocator is the default.  It is