Cleanup of the windows VFS, including added support for Cygwin, fixes

for compiler warnings under unusual configurations, and improved diagnostic
error messages.

FossilOrigin-Name: c94933f13208f3f7d6d1b117ce6d2821100655a4

diff --cc manifest
index 0b5fa83aa73ba7f09e2bfbc7425f369f4d6e6f2f,8d15520f4c8651b59c2b0da27b7c395ba5729128..20e7aec2b2aef25712645d8d681987a9472e26dd
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\sa\sproblem\scausing\sSQLite\snot\sto\suse\sstat4\sor\sstat3\sdata\sto\sanalyze\sconstraints\sof\sthe\sform\s"column\s=\sexpr\sCOLLATE\scollation"\s(those\swith\san\sexplicit\sCOLLATE\son\sthe\snon-column\sside\sof\sthe\scomparison\soperator).
- D 2013-08-31T17:21:26.324
 -C Revise\sthe\samalgamation\stool\sto\sallow\s'duplicate'\sinclude\sfiles\sto\sbe\sretained\smanually\swhile\sstill\spreserving\sthe\sexisting\sline\snumbers.
 -D 2013-08-31T18:06:52.923
++C Cleanup\sof\sthe\swindows\sVFS,\sincluding\sadded\ssupport\sfor\sCygwin,\sfixes\nfor\scompiler\swarnings\sunder\sunusual\sconfigurations,\sand\simproved\sdiagnostic\nerror\smessages.
++D 2013-08-31T18:36:14.237
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 5e41da95d92656a5004b03d3576e8b226858a28e
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1109,7 -1109,7 +1109,7 @@@ F tool/warnings-clang.sh f6aa929dc20ef1
  F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
  F tool/wherecosttest.c f407dc4c79786982a475261866a161cd007947ae
  F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
- P d9fadc8fa6ef02d516678d57896d93e0a5f52cfe
- R 549c9915be9450c721bff69cc42a239a
- U dan
- Z dce49f1165decc3594690bec1fb4ef74
 -P b1811baab6e35ecb1ba920a7ed3302997758d309
 -R c09e9aaa82ece462d9ada3bc7aee07de
 -U mistachkin
 -Z 9761d739f96263a417653d62e6565ea2
++P 1e86d81d46c9da6aaee0c6938ee40933f35e3d0d aa48284637b954d63bcf77e19b25e75c7ad1a6d3
++R 86ece7a1f31f0a8c4eaf6a2aa2ba8fd5
++U drh
++Z 6d21523c19e589363df183a571e778f3

diff --cc manifest.uuid
index 89b7c2ebb766abcfdfed4c5ce71861c63914efa6,f86d289b7db05136dd71e483dc8a296a5dd28431..6278beba1be28e46717d8b52def343cbd68d7114
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 1e86d81d46c9da6aaee0c6938ee40933f35e3d0d
 -aa48284637b954d63bcf77e19b25e75c7ad1a6d3
++c94933f13208f3f7d6d1b117ce6d2821100655a4