build problems(php4)

Hi, when I build php4.2.1 on sun solaris 8. I get the following error: # make Making all in Zend /bin/sh ../libtool --silent --mode=compile gcc -DHAVE_CONFIG_H -I. -I.. -I../main     -D_POSIX_PTHREAD_SEMANTICS -I../TSRM  -g -O2 -prefer-non-pic -static -c -o z end_language_parser.lo test -f zend_language_parser.c || echo './'zend_languag e_parser.c In file included from zend_compile.h:24,                  from zend_language_parser.c:147: zend.h:55: unix.h: No such file or directory *** Error code 1 make: Fatal error: Command failed for target `zend_language_parser.lo' Current working directory /usr/local/php-4.2.1/Zend *** Error code 1 make: Fatal error: Command failed for target `all-recursive' I would appreciate if anyone can direct me to a solution. Thanks . Yong Zhang -- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.