In the Sybase section, the configure script adds to the $LIBS variable the library "sybtcl" which does not exists in my system. I take a look in the Sybase directory and I found only the "tcl" library. When configuring the other extensions (eg. zlib), the scritp fails because it tries to use the non-existant sybtcl library while compiling the test programs "conftest".

Moreover the tcl library in /usr/local/lib (owned by the tcl/tk package)  takes the precedence on the Sybase tcl library located in my Sybase directory.

My configure line is:

./configure --with-apache=../apache \
               --with-config-file-path=/usr/local/apache/etc \
               --with-sybase-ct=/sybase \
               --with-oci8 --with-oracle \
               --with-gdbm --with-gd --with-pdflib --with-zlib \
               --with-jpeg-dir=/usr/local --with-tiff-dir=/usr/local \
               --enable-calendar --enable-dbase --enable-yp \
               --enable-versioning --enable-track-vars \
               --enable-ftp --enable-trans-sid \
               --enable-sysvsem --enable-sysvshm

This is the tail of the generated config.log file:

configure:41154: checking whether to include zlib support
configure:41343: checking for gzgets in -lz
configure:41362: gcc -o conftest -g -O2  -D_POSIX_PTHREAD_SEMANTICS -DXML_BYTE_ORDER=21 -L/usr/loc
al/lib  -R/usr/ucblib -L/usr/ucblib -R/usr/local/lib -L/usr/local/lib -R/export/home/oracle/lib -L
/export/home/oracle/lib -R/sybase/lib -L/sybase/lib conftest.c -lz  -lsybtcl -lintl -lcomn -lct -l
cs -lz -ljpeg -lpng -ltiff -lpdf -lclntsh -ldl -lgen -lsocket -lnsl -lclntsh -ldl -lgen -lsocket -
lnsl -lttf -ljpeg -lz -lpng -lgd -lgdbm -lresolv -lresolv -lm -ldl -lcrypt -lnsl -lsocket  -lsocke
t -L/usr/local/lib -ljpeg 1>&5
ld: fatal: library -lsybtcl: not found
ld: fatal: File processing errors. No output written to conftest
collect2: ld returned 1 exit status
configure: failed program was:
#line 41351 "configure"
#include "confdefs.h"
/* Override any gcc2 internal prototype to avoid an error.  */
/* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
char gzgets();

int main() {
gzgets()
; return 0; }