Update sqlite to 3.7.3.

third_party/sqlite/src/configure.ac

 #
 # The build process allows for using a cross-compiler.  But the default
 # action is to target the same platform that we are running on.  The
 # configure script needs to discover the following properties of the 
 # build and target systems:
 #
 #    srcdir
 #
 #        The is the name of the directory that contains the
 #        "configure" shell script.  All source files are
@@ skipping 121 matching lines @@
 #########
 # By default, we use the amalgamation (this may be changed below...)
 #
 USE_AMALGAMATION=1
 
 #########
 # See whether we can run specific tclsh versions known to work well;
 # if not, then we fall back to plain tclsh.
 # TODO: try other versions before falling back?
 # 
-AC_CHECK_PROGS(TCLSH_CMD, [tclsh8.4 tclsh], none)
+AC_CHECK_PROGS(TCLSH_CMD, [tclsh8.5 tclsh], none)
 if test "$TCLSH_CMD" = "none"; then
   # If we can't find a local tclsh, then building the amalgamation will fail.
   # We act as though --disable-amalgamation has been used.
   echo "Warning: can't find tclsh - defaulting to non-amalgamation build."
   USE_AMALGAMATION=0
   TCLSH_CMD="tclsh"
 fi
 AC_SUBST(TCLSH_CMD)
 
 AC_ARG_VAR([TCLLIBDIR], [Where to install tcl plugin])
@@ skipping 557 matching lines @@
 AC_CONFIG_HEADERS(config.h)
 
 #########
 # Generate the output files.
 #
 AC_SUBST(BUILD_CFLAGS)
 AC_OUTPUT([
 Makefile
 sqlite3.pc
 ])