Avoid using posix_fallocate() in WAL mode, as it is not supported by all file-systems.

FossilOrigin-Name: 1bbb4be1a25947f75b2b0c6f368199016b6f7de3

diff --cc manifest
index 59fe24e66e032327f7935c017e9e81634f037391,72d6bee5a42f8b1c8067ea86e125fff61271ea71..de4051d5666e5de3738a6da51338ee2df572b3c6
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Update\sdocumentation\swith\snew\shyperlinks.\s\sNo\schanges\sto\scode.
- D 2013-04-26T15:55:57.095
+ C Avoid\susing\sposix_fallocate()\sin\sWAL\smode,\sas\sit\sis\snot\ssupported\sby\sall\sfile-systems.
 -D 2013-04-26T16:09:29.947
++D 2013-04-26T17:00:52.665
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in ce81671efd6223d19d4c8c6b88ac2c4134427111
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1062,7 -1062,10 +1062,7 @@@ F tool/vdbe-compress.tcl f12c884766bd14
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
  F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
--P 49d23ef61f9ce2ffe13237b51a0e01b0b46ba96b
- R 9dfdc1bbf9c2e5197fa469091ec011ea
- U drh
- Z 247eb74d6133c2eb692e1fce731d0d35
 -R c26b6b9eda44a997204fb8564cbd02a4
 -T *branch * avoid-fallocate
 -T *sym-avoid-fallocate *
 -T -sym-trunk *
++P 640eb54ad6aac9bc7109cba167389a9bcec3f21e 9c7523dabf4aee609287732ce787c9b9a9087e7f
++R b4ea9ecffc738493e7005d865dad4b9a
+ U dan
 -Z 8ca670519b4ace84695b56a8d0f2a643
++Z 8914d43d4bd2278afd40d03ae3982d74

diff --cc manifest.uuid
index de2ac0cb317ebbc49874cafe99584c39a9fa1e91,a357f425fcb6f69fb9e6626144d779a27e585fbb..86ca24f5f4ea3536deaa13ed11de1edcd5e8d005
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 640eb54ad6aac9bc7109cba167389a9bcec3f21e
 -9c7523dabf4aee609287732ce787c9b9a9087e7f
++1bbb4be1a25947f75b2b0c6f368199016b6f7de3