Merge from trunk the ability to use sqlite3_sql interfaces in extensions.

FossilOrigin-Name: 5bb9e6a9f19f9d73314b08afbecb13f46b0cf7b27bfb567960d8f60e3a7a74a1

diff --cc manifest
index e86adf5c12beceeb6b009cc924f55b3f55c538ce,e3e4b89d5218e87902899f578e68fd7c46a05127..bb63b6e40e4c8bf689819b29575fc4423bd2e9cf
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\sthe\sgeopoly_json()\sinterface.\s\sUntested.
- D 2018-05-09T15:00:36.551
 -C Add\s14\snew\sinterfaces\sto\sthe\sloadable\sextension\smechanism.
 -D 2018-05-09T15:17:02.669
++C Merge\sfrom\strunk\sthe\sability\sto\suse\ssqlite3_sql\sinterfaces\sin\sextensions.
++D 2018-05-09T15:19:41.906
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  F Makefile.in bfc40f350586923e0419d2ea4b559c37ec10ee4b6e210e08c14401f8e340f0da
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diff --cc manifest.uuid
index 08afa8abc1355e517d8e57b1d14bd1fe007720c5,8c0653b8f9b143758b7d8078def1f7996ce86498..2f192c2231a1eaae644d93cd29dcb3ae6f8b8cc4
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
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