I'm compiling PHP3.0.2a as an Apache 1.3.1 module on Solaris 2.5.1 using gcc 2.7.2. I'm an old hand with PHP, so I prefer to use the ./setup script to configure things. Everything seems fine in the PHP build, but when I ./Configure and try to make Apache, compilation fails with

<=== src/modules
gcc -c  -I./os/unix -I./include   -DSOLARIS2=251 -DUSE_HSREGEX -DSERVER_SUBVERSION=\"PHP/3.0.2a\" `./apaci` modules.c
gcc -c  -I./os/unix -I./include   -DSOLARIS2=251 -DUSE_HSREGEX -DSERVER_SUBVERSION=\"PHP/3.0.2a\" `./apaci` buildmark.c
gcc  -DSOLARIS2=251 -DUSE_HSREGEX -DSERVER_SUBVERSION=\"PHP/3.0.2a\" `./apaci`    \
      -o httpd buildmark.o modules.o  modules/standard/libstandard.a  modules/php3/libphp3.a  main/libmain.a  ./os/unix/libos.a  ap/libap.a regex/libregex.a  -Lmodules/php3 -L../modules/php3 -L../../modules/php3 -lmodphp3            -L/spare/msql/lib -lmsql         -L/spare/gd/lib -lgd    -lm -ldl -lnsl -lsocket  -lresolv  -lsocket -lnsl
Undefined			first referenced
 symbol  			    in file
charset_vbprintf                    modules/php3/libphp3.a(main.o)
ld: fatal: Symbol referencing errors. No output written to httpd
*** Error code 1
make: Fatal error: Command failed for target `target_static'
Current working directory /spare/apache/src
*** Error code 1
make: Fatal error: Command failed for target `build-std'
Current working directory /spare/apache
*** Error code 1
make: Fatal error: Command failed for target `build'