hg: ppc-aix-port/jdk7u/jdk: Updated using pthreads in java_md_solinux.c to just rely on USE_PTHREADS. Removed the superflous __linux__ as USE_PTHREADS is already explictly turned on for linux builds

[Neil Richards]

On Tue, 2012-07-17 at 08:21 +0200, Thomas Stüfe wrote:
> Hi Neil,
> 
> >
> > On AIX, CPPFLAGS is used for invocations of the C++ compiler (the 'PP'
> > standing for 'Plus-Plus').
> >
> > On Linux, CPPFLAGS is for the C Pre-Processor, and so is used for
> > invocations of both the C and C++ compilers.
> > (Linux has CXXFLAGS for C++-specific options).
> >
> > So, on Linux, adding to CPPFLAGS_COMMON should cater for both scenarios,
> > I believe, whilst on AIX, one needs to add to both CPPFLAGS_COMMON and
> > CFLAGS_COMMON.
> 
> Are you sure this is right? I could not find any documentation for
> that, e.g. on the xlC manuals.
> 
> Reason I ask is I always thought both CXXFLAGS and CPPFLAGS originally
> came from the GNU automake toolchain, and that what you describe as
> "the Linux way" is just the correct way to use those variables - but
> that many people use CPPFLAGS as "C++-Flags" because that is the first
> thing which comes to mind.
> 
> I may be wrong. I think it's mostly all convention anyway, the only
> tools I think do something with those variables are autoconf/automake.
> 
> When working on the AIX port of the SAP JVM, we tried to keep the GNU
> meaning of CPPFLAGS intact: CPPFLAGS for -D../-I.., CXXFLAGS/CFLAGS
> for languange specific settings. However, this has the tendency to
> detoriate, so you probably will find both meanings in the makefiles.
> 
> Kind Regards,
> Thomas Stuefe
> SAP Germany
> 

Hi Thomas,
To be honest, I'm more certain on the Linux side of this story than I am
on the AIX side. :-)

When writing the reply, I did find some references via Google that
seemed to confirm the AIX story I was spinning. Naturally, as I didn't
take a note of them at that point, trying to track those references down
again has proven elusive, thus casting doubt on their validity.

Obviously, the use of these variables is controlled by the make
environment, rather than the compiler, as it is the (potentially
implicit) rules in the make system that use the variables (in whatever
combination) to give command line options to the compiler.

So, if/as it's GNU make being used on both systems, I suppose it makes
sense its behaviour re. these variables should also be (made to be)
similar.

If this is  the case, I'm hoping I'll see duplication of
(-DUSE_PTHREADS) options when compiling C++ code (with Steve's change)
on AIX. If I see that, I'll have confirmation as to what correction to
Steve's change is necessary to bring the use of these variables into
line (with the GNU make / autoconf / automake) norm.

If that option isn't duplicated in the invocation of the C++ compiler on
AIX, it may suggest there are other factors in play (eg. the implicit
rule for C++ compilation is being overridden somewhere). In that case,
I'll have to dig deeper to figure out what's going on.

Regards,
Neil

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