Enable SQLite to use mmap for file access.

The time it takes to issue "SELECT * FROM tvshowview" (the first time the
TV Shows library is opened) with 345 TV shows on a non-overclocked
Raspberry Pi changed as follows. Times are in seconds:

      Before          After
      Mean   StdDev   Mean   StdDev  Confidence  Change
Time  3.352  0.132    2.550  0.021   100.0%      +31.5%

These times assume SQLite has already been upgraded to version 3080301
(see PR xbmc#4235).

tools/depends/target/sqlite3/Makefile

@@ -10,7 +10,7 @@ ARCHIVE=$(SOURCE).tar.gz
 
 # configuration settings
 export CXXFLAGS+=-DSQLITE_ENABLE_COLUMN_METADATA=1
-export CFLAGS+=-DSQLITE_TEMP_STORE=3
+export CFLAGS+=-DSQLITE_TEMP_STORE=3 -DSQLITE_DEFAULT_MMAP_SIZE=0x10000000
 export TCLLIBDIR=/dev/null
 CONFIGURE=cp -f $(CONFIG_SUB) $(CONFIG_GUESS) .; \
           ./configure --prefix=$(PREFIX) --disable-shared \