upgrade tags to rc4

syntax apparently does not work for all toolchains on that platform.
Per Honda Shigehiro.

request packet, use pqReadData().  This has the same effect since
conn->ssl isn't set yet and we aren't expecting more than one byte.
The advantage is that we will correctly detect loss-of-connection
instead of going into an infinite loop.  Per report from Hannu Krosing.

discussion on pgsql-hackers-win32 list.  Documentation still needs to
be tweaked --- I'm not sure how to refer to the APPDATA folder in
user documentation.

consistent.  On Unix we now always consult getpwuid(); $HOME isn't used
at all.  On Windows the code currently consults $USERPROFILE, or $HOME
if that's not defined, but I expect this will change as soon as the win32
hackers come to a consensus.  Nothing done yet about changing the file
names used underneath $USERPROFILE.

subroutine that can hide platform dependencies.  The WIN32 path is still
a stub, but I await a fix from one of the win32 hackers.
Also clean up unnecessary #ifdef WIN32 ugliness in a couple of places.

Michael Fuhr.

dangling cross-references.

< * Allow building with directories containing spaces
> * Allow building in directories containing spaces
<   There are two capabilities here, first the ability to build from a
<   source directory that contains spaces, and second the ability to install
<   into a directory that contains spaces.  The first is probably not
<   possible because 'gmake' and other compiler tools do not fully support
<   spaces in path names.  The second is possible with proper quoting in
<   the makefiles.  Because PostgreSQL supports relocatable installs, it
<   is possible to install into a directory that doesn't contain spaces and
<   then copy the install to a directory with spaces.
>   This is probably not possible because 'gmake' and other compiler tools
>   do not fully support quoting of paths with spaces.
>
> * Allow installing to directories containing spaces
>
>   This is possible if proper quoting is added to the makefiles for the
>   install targets.  Because PostgreSQL supports relocatable installs, it
>   is already possible to install into a directory that doesn't contain
>   spaces and then copy the install to a directory with spaces.

>   There are two capabilities here, first the ability to build from a
>   source directory that contains spaces, and second the ability to install
>   into a directory that contains spaces.  The first is probably not
>   possible because 'gmake' and other compiler tools do not fully support
>   spaces in path names.  The second is possible with proper quoting in
>   the makefiles.  Because PostgreSQL supports relocatable installs, it
>   is possible to install into a directory that doesn't contain spaces and
>   then copy the install to a directory with spaces.

 Viktor Vislobokov