Re: Darwin universal binaries and LDFLAGS conundrum

[Martin-Gilles Lavoie]

On 23 mai 2007, at 10:03, Martin-Gilles Lavoie wrote:

[snip]

> To resume the problem, I need to build a Universal Binary (aka, PPC  
> + i386) library of BerkeleyDB. Now, normally, this is a simple task  
> but it seems Autoconfig is working against me.
>
> At the strict minimum, I need to have the following flags set in  
> the generated makefile:
>
> 	CFLAGS=		-c $(CPPFLAGS) -O3 -isysroot /Developer/SDKs/ 
> MacOSX10.4u.sdk -arch i386 -arch ppc
>         LDFLAGS=        -Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk

[snip]

This is just an update on the status of my problem for you guys to be  
curious at. At this moment, I'm waiting for some info from the  
BerkeleyDB guys (their autoconf environment in particular). There's  
not much you guys can act upon but some details I've uncovered  
recently might be of interest to some readers of this list.

I've learned a few things in the past few days as far as this thing  
is concerned. For one, Tiger and Leopard environment differ in  
significant ways; not that I didn't expect otherwise but the extent  
of the changes still surprised me.

Under Tiger, specifically on a PPC machine, one needs the -isysroot  
flag being passed to CFLAGS and LDFLAGS, targeting the 10.4u SDK  
because the base OS is not universal. Under Intel machines, all  
installed libraries are universal and the use of the 10.4u SDK is not  
required. In fact, passing the 10.4u SDK seems to confuse the  
compiler more than anything.

What's more, under Leopard, the PPC base OS is exactly like the  
Intel: universal.

Thus, I need to further tweak my .ac script with the following:

#       ...
        darwin8.*)
        LDFLAGS="-Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk";;
#       ...
        case "$host_os" in
	darwin8*)	CFLAGS="$CFLAGS -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
arch i386 -arch ppc";;
        darwin9*)       CFLAGS="$CFLAGS -arch i386 -arch ppc";;
        esac
#       ...

Disclaimer: the above would still require a tweak for Tiger-on-Intel  
build environments.

Autoconf requires the m4 macro tool (I didn't bother figuring out  
what it does--I'm lazy that way), but realized that he up-to-date  
version of m4 is 1.4.7 wich is required by autoconf to complete all  
tests and produce a complete-enough configure script as required by  
that berkeleyDB thing. Tiger (darwin8) ships with an antiquated m4,  
at version 1.4.1, while Leopard has 1.4.6.

Under Leopard, autoconf still wasn't able to produce me an adequate  
configure script given our .ac script. So, I'm enquiring about the  
environment under wich the BDB folks built their configure script.

So, a manually-tweaked configure (or Makefile) does (now) produce the  
required output on PPC-* or Intel-Leopard:

        blackhole:build_mac lavoie$ file .libs/libdb-4.5.a
        .libs/libdb-4.5.a: Mach-O universal binary with 2 architectures
	.libs/libdb-4.5.a (for architecture i386):	current ar archive random  
library
	.libs/libdb-4.5.a (for architecture ppc):	current ar archive random  
library

I'll let you know when I have more details for your curiosity and  
your own respective projects, as I get them.

Martin-Gilles Lavoie | Senior software developer | 514.905.8658
Oracle - Macintosh Native Desktop Client, Beehive
600, boul. de Maisonneuve West, Suite 1900 | Montréal (Québec)  H3A 3J2