Upgrade to sqlite3 3.7.4.
diff --git a/PCbuild/readme.txt b/PCbuild/readme.txt
index 48ff8eb..dbe031f 100644
--- a/PCbuild/readme.txt
+++ b/PCbuild/readme.txt
@@ -104,7 +104,7 @@
Python-controlled subprojects that wrap external projects:
_sqlite3
- Wraps SQLite 3.6.21, which is currently built by sqlite3.vcproj (see below).
+ Wraps SQLite 3.7.4, which is currently built by sqlite3.vcproj (see below).
_tkinter
Wraps the Tk windowing system. Unlike _sqlite3, there's no
corresponding tcltk.vcproj-type project that builds Tcl/Tk from vcproj's