New s_lock.h fails on HPUX with gcc

... because the conditional structure assumes that pgsql will only be
built with non-gcc compilers on HPUX.

This is an entirely bogus assumption not only for HPUX, but for any
other architecture that has gcc available.

To be able to compile, I just duplicated the "#if defined(__hpux)"
block into the "#if defined(__GNUC__)" part of the file, but that's
a pretty grotty hack.  I think that the right way to structure the
file is just this:


#if defined(HAS_TEST_AND_SET)

#if defined(somearchitecture)

#if defined(__GNUC__)
// inline definition of tas here
#else
// non-inline definition of tas here, if default isn't adequate
#endif

// machine-dependent-but-compiler-independent definitions here

#endif /* somearchitecture */

// ... repeat above structure for each architecture supported ...


#if !defined(S_LOCK)
// default definition of S_LOCK
#endif

// default definitions of other macros done in the same way

#endif /* HAS_TEST_AND_SET */


On architectures where we don't have any special inline code for GCC,
the inner "#if defined(__GNUC__)" can just be omitted in that
architecture's block.

The existing arrangement with an outer "#if defined(__GNUC__)" doesn't
have any obvious benefit, and it encourages missed cases like this one.


BTW, I'd suggest making the definition of clear_lock for HPUX be

static const slock_t clear_lock =
{{-1, -1, -1, -1}};

The extra braces are needed to suppress warnings from gcc, and declaring
it const just seems like good practice.

            regards, tom lane