Remove lots of code used to support legacy Windows version (WindowsXP and

before).  Use Slim Reader/Writer Locks on Windows for non-recursive mutexes,
since SRWLs are now available on all supported Windows platforms.

FossilOrigin-Name: 6f7a5ff22db10f889596239aae5f6a1130cbdfe72612ceee68cbeb3b86e40227

diff --cc manifest
index 26177c42f818a49e91c65fc4fded186ba787d2f0,fba190ee85b78aabfb4a953199344f0ebe0fe3be..363fb521efe7b5ff0dfa941ffee7371059d05ed4
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\sa\sharmless\scompiler\swarning\sin\ssrc/mutex_w32.c.
- D 2026-04-30T15:41:01.004
 -C Reduce\sthe\snumber\sof\ssystem\scalls\sin\sthe\sos_win.c\sthunk\sfrom\s81\sdown\nto\s58,\sas\swell\sas\sother\ssimplifications.
 -D 2026-04-29T16:09:47.869
++C Remove\slots\sof\scode\sused\sto\ssupport\slegacy\sWindows\sversion\s(WindowsXP\sand\nbefore).\s\sUse\sSlim\sReader/Writer\sLocks\son\sWindows\sfor\snon-recursive\smutexes,\nsince\sSRWLs\sare\snow\savailable\son\sall\ssupported\sWindows\splatforms.
++D 2026-04-30T16:52:56.260
  F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@@ -2203,8 -2203,8 +2203,9 @@@ F tool/warnings-clang.sh bbf6a1e685e534
  F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
  F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
  F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
- P 9012f8ea7454bbb792b4361ed74d778e02b98ef44a443f9a23a27a4222fda747
- R f60cecd3ae6525706eb78da5f4621cdb
 -P f2aa6b66d2a1b5bb2dc8a44788a061a549a846244354df19b44398839578461e
 -R 2b3672c838a493907ddf438bd7d4e49c
++P 8de796ca459f2c996937fe1107838b217572636110c8c09e358343385bf17a1b c49521739c961ed5e38424bf26b2e34d8017a85122622ceac5af7398233fe343
++R 60411fbd5c56fea1097d49a37ccb625f
++T +closed c49521739c961ed5e38424bf26b2e34d8017a85122622ceac5af7398233fe343
  U drh
- Z 523ca6a0971f8bb563e97d91b703dda1
 -Z 76bc5d65524dba7586bb6560dacbd1e4
++Z b0ea9a70b44c85f95eb8bddd4f20e3fc
  # Remove this line to create a well-formed Fossil manifest.

diff --cc manifest.uuid
index 162d9617b1b56eda43493df0a175942a063a8504,598f813fe343b024b7e972981e62896fa5e49a21..b8bb94353fc0944a7c5729d657c02e2a18c04673
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 8de796ca459f2c996937fe1107838b217572636110c8c09e358343385bf17a1b
 -c49521739c961ed5e38424bf26b2e34d8017a85122622ceac5af7398233fe343
++6f7a5ff22db10f889596239aae5f6a1130cbdfe72612ceee68cbeb3b86e40227