* PHP-7.3:
  Fix #78982: pdo_pgsql returns dead persistent connection

Call PQconsumeInput() before PQstatus() to update the status.

* PHP-7.3:
  Fix #78980: pgsqlGetNotify() overlooks dead connection

pgsqlGetNotify() didn't check result of PQconsumeInput().

The php_stream_read() and php_stream_write() functions now return
an ssize_t value, with negative results indicating failure. Functions
like fread() and fwrite() will return false in that case.

As a special case, EWOULDBLOCK and EAGAIN on non-blocking streams
should not be regarded as error conditions, and be reported as
successful zero-length reads/writes instead. The handling of EINTR
remains unclear and is internally inconsistent (e.g. some code-paths
will automatically retry on EINTR, while some won't).

I'm landing this now to make sure the stream wrapper ops API changes
make it into 7.4 -- however, if the user-facing changes turn out to
be problematic we have the option of clamping negative returns to
zero in php_stream_read() and php_stream_write() to restore the
old behavior in a relatively non-intrusive manner.

RFC: https://wiki.php.net/rfc/tostring_exceptions

And convert some object to string conversion related recoverable
fatal errors into Error exceptions.

Improve exception safety of internal code performing string
conversions.

Autoconf defines PACKAGE_* symbols:
- PACKAGE_NAME
- PACKAGE_VERSION
- PACKAGE_TARNAME
- PACKAGE_STRING
- PACKAGE_BUGREPORT
- PACKAGE_URL

and appends them to the generated config.h.in files. With AC_INIT change
via afd52f9d9986d92dd0c63832a07ab1a16bf11d53 where package version, URL,
bug report location and similar meta data are defined, these
preprocessor macros are then non empty strings in the generated
configuration header file. When using phpize, PHP shares the config
files in extensions, warnings of redefined macros appear, such as:
- `warning: 'PACKAGE_NAME' macro redefined`

This patch now disables these non utilized symbols in the generated
config header files.

Better practice would be to include only API specific headers where
needed but this would require even more refactorings. Some extensions
such as pcre, pgsql, and pdo_pgsql solve this issue by undefining some
of these symbols before including the library configuration headers in
the code also. Because these symbols can be defined by any library which
uses Autotools.

Additionally, the unused PACKAGE_* symbols were cleaned for the bundled
libmbfl library and with this patch not needed undef code removed.

This patch removes the so called local variables defined per
file basis for certain editors to properly show tab width, and
similar settings. These are mainly used by Vim and Emacs editors
yet with recent changes the once working definitions don't work
anymore in Vim without custom plugins or additional configuration.
Neither are these settings synced across the PHP code base.

A simpler and better approach is EditorConfig and fixing code
using some code style fixing tools in the future instead.

This patch also removes the so called modelines for Vim. Modelines
allow Vim editor specifically to set some editor configuration such as
syntax highlighting, indentation style and tab width to be set in the
first line or the last 5 lines per file basis. Since the php test
files have syntax highlighting already set in most editors properly and
EditorConfig takes care of the indentation settings, this patch removes
these as well for the Vim 6.0 and newer versions.

With the removal of local variables for certain editors such as
Emacs and Vim, the footer is also probably not needed anymore when
creating extensions using ext_skel.php script.

Additionally, Vim modelines for setting php syntax and some editor
settings has been removed from some *.phpt files.  All these are
mostly not relevant for phpt files neither work properly in the
middle of the file.