Add the SQLITE_DEFAULT_SYNCHRONOUS and SQLITE_DEFAULT_WAL_SYNCHRONOUS

compile-time options.  Automatically switch to the WAL_SYNCHRONOUS setting
when first opening a WAL-mode database if the synchronous setting has not
been previously set by the application.

FossilOrigin-Name: 5a847a676e756bbe33436596d4279f339bfb247c

diff --cc manifest
index 27e5d3a87d8e82327da7595891d9377f3faf2955,f00f793ab64bac8b41fd6a873b20eb0bfa818e81..fb6a8626354a9553965b77fa96dd9c0cb96bb26d
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Update\sfts3/4\sso\sthat\sthe\s'merge=X,Y'\scommand\smerges\sat\sleast,\sinstead\sof\sexactly,\sY\ssegments\sfrom\sa\ssingle\slevel.\sThis\smatches\sthe\sdocumentation.\s'merge=X,0'\sis,\sas\sit\swas\sin\s3.11,\san\serror.
- D 2016-03-08T15:37:48.202
 -C Make\sthe\sSQLITE_DEFAULT_SYNCHRONOUS\sand\sSQLITE_DEFAULT_WAL_SYNCHRONOUS\nvalues\szero-based\sto\sagree\swith\sPRAGMA\ssynchronous.
 -D 2016-03-08T15:30:01.003
++C Add\sthe\sSQLITE_DEFAULT_SYNCHRONOUS\sand\sSQLITE_DEFAULT_WAL_SYNCHRONOUS\ncompile-time\soptions.\s\sAutomatically\sswitch\sto\sthe\sWAL_SYNCHRONOUS\ssetting\nwhen\sfirst\sopening\sa\sWAL-mode\sdatabase\sif\sthe\ssynchronous\ssetting\shas\snot\nbeen\spreviously\sset\sby\sthe\sapplication.
++D 2016-03-08T15:47:47.861
  F Makefile.in f53429fb2f313c099283659d0df6f20f932c861f
  F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
  F Makefile.msc df0bf9ff7f8b3f4dd9fb4cc43f92fe58f6ec5c66
@@@ -1454,7 -1454,7 +1454,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P c4e192a0e5a408e198dbacb2752859a00d2b572f
- R 3e8d6ecab7b420c32f9b7a175d510e4d
- U dan
- Z 45820e8758a67cfc47c6d8f8a214769a
 -P 5791407b523abd24e832fc2361b3e9f01ee2f36a
 -R bba2e4d185d472ce58e719fcfcf03f67
++P 64b3cb29159491cbfab7e01844b54408541ece5e 592d2104361500e5002783ba329a2609389c57b9
++R da9c8dcc67c43bdd497418f56500542e
++T +closed 592d2104361500e5002783ba329a2609389c57b9
+ U drh
 -Z 6f7df0629a8472a1465e8e2960a9953c
++Z 4fa68fdb2896879ae18878d725366e25

diff --cc manifest.uuid
index 5eb2c62ef92deabb8eaccc8b896307d365515350,ba3ff1f350ad765fd2dba7d5e3c5883827db75d9..0dbae66e0eae2bd902bf1730606ed5d199eb1f22
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 64b3cb29159491cbfab7e01844b54408541ece5e
 -592d2104361500e5002783ba329a2609389c57b9
++5a847a676e756bbe33436596d4279f339bfb247c