Look into your config log for "length prototypes and stdarg.h" - does this check fail for you?
If yes, for which reason?

checking, seems *no* failure ...  from config.log:

...
configure:68143: checking for external libmbfl
configure:68161: result: no
configure:68181: checking for variable length prototypes and stdarg.h
configure:68220: gcc -o conftest -I/usr/local/include -g -O2 -I/usr/local/mysql/include/mysql -I/usr/local/berkeley-db/include -I/usr/local/include -I/usr/local/ssl/include -I/usr/local/ncurses/include -no-cpp-precomp -liconv -L/usr/local/lib -L/usr/local/berkeley-db/lib -bind_at_load -L/usr/local/mysql/lib/mysql -lmysqlclient_r -L/usr/local/berkeley-db/lib -ldb -L/usr/local/lib -lpcre -L/usr/local/ssl/lib -lssl -lcrypto -L/usr/local/ncurses/lib -lncurses  -L/usr/local/lib -L/usr/local/lib -L/usr/local/ssl/lib -L/usr/local/ssl/lib -L/usr/local/berkeley-db/lib -L/usr/local/berkeley-db/lib -L/usr/X11R6/lib -L/usr/X11R6/lib -L/usr/local/gd/lib -L/usr/local/gd/lib conftest.c -liconv -lgmp -lintl -lgd -lfreetype -lX11 -lXpm -lpng -lz -ljpeg -lssl -lcrypto -lpcre -ldb-4.3 -ldb-4.3 -lcurl -lz -lpcre -lssl -lcrypto -lm  -lxml2 -lz -liconv -lm -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lcurl -lidn -lssl -lcrypto -lz -lxml2 -lz -liconv -lm >&5
configure:68223: $? = 0
configure:68225: ./conftest
configure:68228: $? = 0
configure:68243: result: yes
configure:68256: checking for stdlib.h
configure:68261: result: yes
...

Could you plz check main/php_config.h and tell me what is the value of HAVE_STDARG_PROTOTYPES defined there?

hi tony,

/usr/ports/php-5.2cvs/main  > grep HAVE_STDARG_PROTOTYPES *
  php_config.h:/* #undef HAVE_STDARG_PROTOTYPES */
  php_config.h.in:#undef HAVE_STDARG_PROTOTYPES

Latest CVS works just fine here.

FWIW, I'm getting this on 5.1.4. I DO have an entry in my 
config.log though:

configure:52940: checking for variable length prototypes and 
stdarg.h
configure:52974: gcc -o conftest -I/usr/include -mtune=7450 
-mcpu=7450 -O2 -pipe -maltivec -mabi=altivec -fno-strict-
aliasing -DBIND_8_COMPAT=1 -DEAPI -I/sw/include -Wno-
pointer-sign -I/sw/include -no-cpp-precomp -liconv -L/usr/
lib -L/sw/lib -L/opt/local/lib -L/opt/local/lib conftest.c -
liconv -lintl -lt1 -lfreetype -lpng -lz -ljpeg -lcurl -lbz2 
-lz -lm  -lxml2 -lz -liconv -lm -lcurl -lssl -lcrypto -lz -
lxml2 -lz -liconv -lm 1>&5
configure: failed program was:
#line 52959 "configure"
#include "confdefs.h"

#include <stdarg.h>
int foo(int x, ...) {
        va_list va;
        va_start(va, x);
        va_arg(va, int);
        va_arg(va, char *);
        va_arg(va, double);
        return 0;
}
int main() { return foo(10, "", 3.14); }

Does that make any more sense?

This thread suggests that this is a problem that was 
introduced with XCode 2.2 and gcc 4.0.1, so if your XCode is 
older then you won't see this error:

http://www.mail-archive.com/fink-devel@lists.sourceforge.net/
msg12622.html
http://thread.gmane.org/gmane.os.apple.fink.general/19723

Assigned to the maintainer.

i've
  xcode 2.4
  gcc version 4.0.1 (Apple Computer, Inc. build 5363)

installed.

bldg with-mbstring _had_ worked w/ this combo ...

though i can't swear to the correlation, i think it was a php52cvs update when it started.

sounds like y'all have a better handle on it atm.

thx.

You can try to grab some old CVS code and see if it builds for you.
This command would do that for you:
cvs -d :pserver:cvsread@cvs.php.net/repository co -D "2006-<month>-<day> 00:00:00" -r PHP_5_2 php-src

And if the old code doesn't work for you too, it's likely to be Xcode issue, not PHP.

Well, given that I'm seeing this in 5.1.4, I doubt earlier 
versions of 5.2 will be any different, and I bet openmacnews 
upgraded XCode between Aug 4th and 14th...

I have however discovered something else: it works fine on 
Intel OS X with XCode 2.4 (MacBook). I'm seeing this problem 
on a Dual G4, also with XCode 2.4. Looking more like a gcc PPC 
issue to me.

>I bet openmacnews upgraded XCode between Aug 4th and 14th...

yup.

> I have however discovered something else: it works fine on 
Intel OS X with XCode 2.4 (MacBook). I'm seeing this problem 
on a Dual G4, also with XCode 2.4. Looking more like a gcc PPC issue to me.

hmm ...

all my tests ARE on PPC -- no MacIntels.

I successfully compiled PHP 5.1.4 on Mac OS X 10.4.6 PPC G4 with a certain set of configure options on June 21, 2006, and today I wanted to upgrade to 5.1.5 but got the aforementioned error. Went back and tried to compile the exact same 5.1.4 that worked before, and got same error. So nothing changed in PHP code, but something that changed in the system. According to my installer receipts, since June 21, I have installed Mac OS X 10.4.7, QuickTime 7.1.2, iTunes 6.0.5, Security Update 2006-004 and Xcode 2.4.

Interestingly before all this trouble I was able to install PHP 5.1.5 through MacPorts with no errors, and it also enables mbstring. I don't know why it works there and not when I compile manually (even using their exact same configure options).

I just got this error with the latest CVS of PHP 5.2.x. I'm 
running XCode 2.4. Is this going to be fixed soon?

This seems like a rerun of a bug I reported about a year 
ago, which has come back to rear its ugky head again....

In 5.2RC3, MacOS 10.4.7, Xcode 2.4, PPC Mac G4 I get:

In file included from /usr/local/src/php-5.2.0RC3/ext/
mbstring/oniguruma/regerror.c:37:
/usr/lib/gcc/powerpc-apple-darwin8/4.0.1/include/varargs.h:
4:2: error: #error "GCC no longer implements <varargs.h>."
/usr/lib/gcc/powerpc-apple-darwin8/4.0.1/include/varargs.h:
5:2: error: #error "Revise your code to use <stdarg.h>."
/usr/local/src/php-5.2.0RC3/ext/mbstring/oniguruma/
regerror.c: In function 'onig_error_code_to_str':
/usr/local/src/php-5.2.0RC3/ext/mbstring/oniguruma/
regerror.c:196: error: parse error before 'va_dcl'
/usr/local/src/php-5.2.0RC3/ext/mbstring/oniguruma/
regerror.c:214: error: parse error before 'OnigErrorInfo'
/usr/local/src/php-5.2.0RC3/ext/mbstring/oniguruma/
regerror.c: In function 'onig_snprintf_with_pattern':
/usr/local/src/php-5.2.0RC3/ext/mbstring/oniguruma/
regerror.c:271: error: parse error before 'va_dcl'
make: *** [ext/mbstring/oniguruma/regerror.lo] Error 1

See Bug #34977.

Since PHP 5.2, newer version of oniguruma (multibyte regex library for Ruby) is bundled.
This problem maybe caused by this change.
I ask for the original author of oniguruma about 
this problem.

It seems to be caused by bugs of gcc 4.0.1 of XCode 2.4 
on Mac OSX PPC.

Can you try gcc-3.3 instead of gcc-4.0.1 ?

$ CC=/usr/bin/gcc-3.3
$ ./configure [options]
$ make

Sorry, but your problem does not imply a bug in PHP itself.  For a
list of more appropriate places to ask for help using PHP, please
visit http://www.php.net/support.php as this bug system is not the
appropriate forum for asking support questions.  Due to the volume
of reports we can not explain in detail here why your report is not
a bug.  The support channels will be able to provide an explanation
for you.

Thank you for your interest in PHP.

This problem is not PHP 5.x issue, but it is caused by
a bug of gcc 4.0.1 in Xcode.

The possible workarounds are,
 1.try newer/better version of XCode.
 2.use gcc-3.3 instead of gcc-4.0.1.
 3.disable compile optimization switch (-O2) 
 4.rewrite  
       #undef HAVE_STDARG_PROTOTYPES
   to
       #define HAVE_STDARG_PROTOTYPES  1
   in main/php_config.h after configure executed.