Patch: Remove gcc dependency in definition of inline functions

Hi,

The attached patch is offered for the 2010-01 commitfest.
It's also available in my git repository in the "submitted" branch:
   http://git.postgresql.org/gitweb?p=users/harriman/share.git;a=shortlog;h=refs/heads/submitted

In palloc.h and pg_list.h, some inline functions are defined if
allowed by the compiler.  Previously the test was gcc-specific.
This patch enables inlining on more platforms, relying on the
Autoconf-generated "configure" script to determine whether
the compiler supports inline functions.

Depending on the compiler, the keyword for defining an inline
function might be spelled as inline, __inline, or __inline__,
or none of these.  "configure" finds out, and except in the
first case, puts a suitable "#define inline" into pg_config.h.
This hasn't changed.

What's new is that "configure" will add "#define HAVE_INLINE 1"
into pg_config.h if it detects that the compiler accepts inline
function definitions.  palloc.h and pg_list.h will condition
their inline function definitions on HAVE_INLINE instead of
the gcc-specific __GNUC__.

After applying the patch, run these commands to update
the configure script and pg_config.h.in:
	autoconf; autoheader

(Does anybody still use a C compiler that doesn't support
inline functions?)

Regards,
... kurt