Change the legacy RC4-based PRNG to use the RFC-7539 chacha20 algorithm.

FossilOrigin-Name: a0f801151925e882e120f6ab685dcacb9d3268d25b52bc665c5b927bcc7dda1e

diff --cc manifest
index abc82a7f17f9516f680243a32583cc67be07e849,db5ad92d5fe12ebef1b7642b05de9506402e6e86..f8f98704b778138162caaf6297a89fb32fdbcb7e
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\sassert()\sstatements\sto\sverify\sthat\sthe\sSQLITE_OPEN_EXCLUSIVE\sflag\sis\salways\spassed\sto\sthe\sVFS\swhen\sopening\sa\stemporary\sfile.
- D 2022-08-16T10:52:35.403
 -C Fix\sobsolete\scomments.\s\sAdd\snew\scomments.\s\sFix\snon-standard\sspacing.
 -D 2022-08-16T16:57:33.367
++C Change\sthe\slegacy\sRC4-based\sPRNG\sto\suse\sthe\sRFC-7539\schacha20\salgorithm.
++D 2022-08-16T17:18:00.622
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1999,8 -1999,8 +1999,9 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P c271096736889530f392ff37e631a77f3bc9c46b290dbda245fa05249f4410fc
- R 3f7d8ed697988ef9ad8d4dda04b632a0
- U dan
- Z 207999dde59e8e595694810745e7b969
 -P 72e220eed446ea9a02a6ef03e09a01bcb8bbca1f3b32d2e0bf52a17d9722e2f0
 -R cdb53b59d0af11c8f66b0b5bb02ede98
++P e123da49ccae61d591abded52f4721aa10f20d75935c9a3e3fe826a9b8df2317 a0d224c6a69941dad1f2b35edcc7ddee343b99eae2aeed74043461f3e97ef5b4
++R d14b7d3bd2befa6e359a3420d9b0b1d1
++T +closed a0d224c6a69941dad1f2b35edcc7ddee343b99eae2aeed74043461f3e97ef5b4
+ U drh
 -Z 1158c2a25804bd20ee35e9fb8e722661
++Z c066b8669f45d6d3a5c825d691d523b1
  # Remove this line to create a well-formed Fossil manifest.

diff --cc manifest.uuid
index 75e42a2853c32376bc15e8c787bbc27e58afc153,54413fbc1b88333c051bccd9616b2483ec765618..f073344af1ebf00d77ffd01966e6bb04ede3b5c5
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- e123da49ccae61d591abded52f4721aa10f20d75935c9a3e3fe826a9b8df2317
 -a0d224c6a69941dad1f2b35edcc7ddee343b99eae2aeed74043461f3e97ef5b4
++a0f801151925e882e120f6ab685dcacb9d3268d25b52bc665c5b927bcc7dda1e