Improve performance of wal-mode locking on unix in cases where there are hundreds...

FossilOrigin-Name: a1c19eea8f141b89a0921da0724096feb21a772ef6654f164e2c36ebf9f7871e

diff --cc manifest
index 8323125ab8c6ae6453ed80af6f308ad0056c922c,5d3cdf5b163e0710724e5dd021b92fbbaa8a3561..c82cf36094170add52d4bdc6c37cdf5436464f44
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\sthe\smiscellaneous\s'series'\sextension\sto\sthe\sshell.
- D 2020-08-28T18:47:39.103
 -C Fix\shandling\sof\san\sxShmLock(SHARED,\sUNLOCK)\scall\swhen\sthe\scaller\sdoes\snot\shold\sany\slock\son\sthe\sspecified\sslot,\sbut\sanother\sconnection\sin\sthe\ssame\sprocess\sholds\san\sEXCLUSIVE.
 -D 2020-08-28T20:01:06.517
++C Improve\sperformance\sof\swal-mode\slocking\son\sunix\sin\scases\swhere\sthere\sare\shundreds\sof\sconnections\sto\sa\ssingle\sdatabase\swithin\sthe\ssame\sprocess.
++D 2020-08-29T15:15:07.650
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1879,7 -1879,7 +1879,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
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  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
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- U mistachkin
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++R e2ba8a5583c80bb95657ae8ebc8ad469
++T +closed 3eb365027b885e1f61965efd53a3643b6ff441ae01e79038a091314516a50dd4
+ U dan
 -Z 13cfa1981b90fb57cb3c9a6bb39ef17d
++Z 6b5d0c223b51bcc2c5b4ad0cc8397b1a

diff --cc manifest.uuid
index 65f7dca15131d6274f3b07b0ee65c87aeab4b6e7,a7a42b45e0004433265b7d626e0229c3ceea1fa1..5ee35afa3ff42b52586ef1c51d4787b2cb2aac3d
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- fc0856dccfab273d50457052fa3c6da768d0eb2504ad04d9540da4e3222fc829
 -3eb365027b885e1f61965efd53a3643b6ff441ae01e79038a091314516a50dd4
++a1c19eea8f141b89a0921da0724096feb21a772ef6654f164e2c36ebf9f7871e