gcc -g -O2 -O2  -I/opt/local/i386/include -I. -I.                     -I/opt/local/i386/imap/include -I/opt/local/i386/include -I/usr/X11R6/include/X11/magick -I/usr/openwin/include/X11 -I/opt/local/i386/mysql/include -I/opt/local/i386/postgres/include -I/usr/include -I/usr/local/include -I/opt/local/i386/include/xml    -c main.c -o main.o
main.c: In function `php3_printf':
main.c:308: `__builtin_va_alist' undeclared (first use in this function)
main.c:308: (Each undeclared identifier is reported only once
main.c:308: for each function it appears in.)
main.c: In function `php3_error':
main.c:381: `__builtin_va_alist' undeclared (first use in this function)

Using "gcc version egcs-2.91.57 19980901 (egcs-1.1 release)".

The cause is the inclusion of "/usr/include" in the Makefile INCLUDE
line.  Dunno where this is generated by configure. /usr/include is
always used by any Unix compiler I've seen so far, but GCC does not
like seeing it before it's own include dir, for obvious reasons.

Removing /usr/include from that line allows the compilation to proceed.