This preserves user-specified LDFLAGS; we already kept user-specified
CFLAGS and CPPFLAGS.  Given the shortage of complaints and the fact that
any problem caused is likely to appear at build time, no back-patch.

Dag-Erling Smørgrav and Noah Misch

This is evidently the default on buildfarm member narwhal, but that
is a pretty ancient Mingw version, and there is reason to think that
more recent versions of GNU ld have this feature turned on by default.
Since we are trying to achieve consistency of link behavior across
all Windows toolchains, let's just make sure here.

linking both executables and shared libraries, and we add on LDFLAGS_EX when
linking executables or LDFLAGS_SL when linking shared libraries.  This
provides a significantly cleaner way of dealing with link-time switches than
the former behavior.  Also, make sure that the various platform-specific
%.so: %.o rules incorporate LDFLAGS and LDFLAGS_SL; most of them missed that
before.  (I did not add these variables for the platforms that invoke $(LD)
directly, however.  It's not clear if we can do that safely, since for the
most part we assume these variables use CC command-line syntax.)

Per gripe from Aaron Swenson and subsequent investigation.

than erroring out.  This is the Unix behavior.

than having CFLAGS= in the template files.

It uses -O2 for gcc (generated by autoconf), and -O for non-gcc, unless
the template overrides it.

        Win32 port is now called 'win32' rather than 'win'
        add -lwsock32 on Win32
        make gethostname() be only used when kerberos4 is enabled
        use /port/getopt.c
        new /port/opendir.c routines
        disable GUC unix_socket_group on Win32
        convert some keywords.c symbols to KEYWORD_P to prevent conflict
        create new FCNTL_NONBLOCK macro to turn off socket blocking
        create new /include/port.h file that has /port prototypes, move
          out of c.h
        new /include/port/win32_include dir to hold missing include files
        work around ERROR being defined in Win32 includes

configure under native Windows (MinGW that is), but you won't get very far
compiling yet.  The dynaloader files are from Jan Wieck's patch set.

Eliminate the mysterious games that the Cygwin build plays with the linker
flag variables.  DLLLIBS is gone, use SHLIB_LINK like everyone else.
Detect cygipc in configure, after the linker flags are set up, otherwise
configure might not work at all.

Make sure everything is covered by make clean.

Fix the build of the new conversion procedure modules.

Add new DLLIMPORT markers where required.

Finally, the compiler complains if we use an explicit
-I/usr/local/include, so don't do that.  Curiously, -L/usr/local/lib is
still necessary.

Makefile.port, since they are of no use to configure and much of the
library magic happens in Makefile.port anyway.

Use __alpha, not __alpha__, since the former is universally available.
Remove -DNOFIXADE from the compile command line and put it in the port
include file.

Read templates after compiler is detected. Convert all templates to real
shell scripts. Rename bsd->openbsd, alpha->osf.