pgsql: Disappearing filedescriptors need to be reported later sometimes.
Update CHANGES.
precompile: Make sure to clamp the integer range correctly.

Fixes issue with Stdio.Buffer()->read_int32() having the type
function(:int(0..-1)).

Fixes [LysLysKOM 21057425]/[Pike mailinglist 14286].

NB: This bug also caused low_describe_type() to loop infinitely
    when describing the return type.
Build: Rerun the precompiler when it has been changed.

Adds a dependency for the generated files on Tools.Standalone.precompile.

Also rewrites the Makefile rules to not use explicit dependencies
in implicit rules, as they seem to be ignored by at least gnu-make.
Standards.URI: Support rel being absolute in combine_uri_path().

Roxen.fix_relative() calls combine_uri_path() with an empty base
and an absolute rel to get rid of path segments with "." and "..".

Fixes Roxen.fix_relative() getting a doubled initial "/".

Also adds a related FIXME in reparse_uri().
pgsql: Only assign _portalname once, small regressionfix.
pgsql: Coalesce packets to reduce overhead.