Looks like your path to the ODBC includes and libraries is not being found.  

After three days of testing, the problem still exists. The path to the includes and libaries are okay, I used the same configuration on SuSE Linux 7.1, there were no errors during the compiling of PHP...

Okay, a new config:

./configure --with-apxs=/usr/local/apache/current/bin/apxs --with-mysql=/usr/local/mysql/ --with-ibm-db2=/home/db2inst1/sqllib --with-gd --with-dom --with-db --with-unixODBC=/usr/local/include/ --with-openssl-include=/usr/local/openssl --with-zlib-dir=/usr/include/  --with-jpeg-dir=/usr/local/lib/ --with-png-dir=/usr/local/lib/ --with-tiff-dir=/usr/local/lib/ --with-ttf-dir=/usr/local/lib/ --with-java=/usr/lib/java/ --with-mcrypt --enable-ftp --enable-calendar --enable-versioning --enable-track-vars=yes --enable-sysvshm=yes --enable-sysvshm=yes --with-config-file-path=/etc --enable-magic-quotes --enable-trans-sid

but the same errors during compiling:

Making all in odbc
make[2]: Entering directory `/usr/local/src/lamp/php-4.2.1/ext/odbc'
make[3]: Entering directory `/usr/local/src/lamp/php-4.2.1/ext/odbc'
/bin/sh /usr/local/src/lamp/php-4.2.1/libtool --silent --mode=compile gcc  -I. -I/usr/local/src/lamp/php-4.2.1/ext/odbc -I/usr/local/src/lamp/php-4.2.1/main -I/usr/local/src/lamp/php-4.2.1 -I/usr/local/apache/1.3.24/include -I/usr/local/src/lamp/php-4.2.1/Zend -I/usr/include/libxml2 -I/usr/local/include -I/usr/local/mysql//include -I/home/db2inst1/sqllib/include -I/usr/local/src/lamp/php-4.2.1/ext/xml/expat  -DLINUX=22 -DMOD_SSL=208108 -DUSE_HSREGEX -DEAPI -I/usr/local/src/lamp/php-4.2.1/TSRM -g -O2 -prefer-pic  -c php_odbc.c
In file included from /home/db2inst1/sqllib/include/sqlcli1.h:42,
                 from php_odbc.h:178,
                 from php_odbc.c:37:
/home/db2inst1/sqllib/include/sqlcli.h:718: warning: `ODBCVER' redefined
php_odbc.h:27: warning: this is the location of the previous definition
php_odbc.c: In function `safe_odbc_disconnect':
php_odbc.c:200: warning: passing arg 1 of `SQLDisconnect' makes integer from pointer without a cast
php_odbc.c:203: warning: passing arg 1 of `SQLTransact' makes integer from pointer without a cast
php_odbc.c:203: warning: passing arg 2 of `SQLTransact' makes integer from pointer without a cast
php_odbc.c:204: warning: passing arg 1 of `SQLDisconnect' makes integer from pointer without a cast
php_odbc.c: In function `_close_odbc_conn':
php_odbc.c:215: warning: passing arg 1 of `safe_odbc_disconnect' makes pointer from integer without a cast
php_odbc.c: In function `_close_odbc_pconn':
php_odbc.c:227: warning: passing arg 1 of `safe_odbc_disconnect' makes pointer from integer without a cast
php_odbc.c: In function `odbc_do_connect':
php_odbc.c:2154: warning: passing arg 1 of `safe_odbc_disconnect' makes pointer from integer without a cast
/bin/sh /usr/local/src/lamp/php-4.2.1/libtool --silent --mode=link gcc  -I. -I/usr/local/src/lamp/php-4.2.1/ext/odbc -I/usr/local/src/lamp/php-4.2.1/main -I/usr/local/src/lamp/php-4.2.1 -I/usr/local/apache/1.3.24/include -I/usr/local/src/lamp/php-4.2.1/Zend -I/usr/include/libxml2 -I/usr/local/include -I/usr/local/mysql//include -I/home/db2inst1/sqllib/include -I/usr/local/src/lamp/php-4.2.1/ext/xml/expat  -DLINUX=22 -DMOD_SSL=208108 -DUSE_HSREGEX -DEAPI -I/usr/local/src/lamp/php-4.2.1/TSRM -g -O2 -prefer-pic   -o libodbc.la  php_odbc.lo
make[3]: Leaving directory `/usr/local/src/lamp/php-4.2.1/ext/odbc'
make[2]: Leaving directory `/usr/local/src/lamp/php-4.2.1/ext/odbc'

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

This should be fixed in this snapshot:

http://snaps.php.net/php4-latest.tar.gz