Compiling 4.0b1 with egcs-2.91.66 works fine with system-regex, but getting lots of errors related to regex.h when using included regex:

gcc -DHAVE_CONFIG_H -I. -I. -I../.. -I../../libzend -I../../TSRM -I/home/campbell/tmp/php-4.0b1/../apache_1.3.6/src/include -I/home/campbell/tmp/php-4.0b1/../apache_1.3.6/src/os/unix   -I/home/campbell/tmp/gd1.6.1 -I/usr/local/openldap/include -I/usr/local/mysql/include/mysql   -I../.. -I../../libzend    -g -O2 -g -c browscap.c
In file included from ../../php_regex.h:5,
                 from browscap.c:22:
../../regex/regex.h:31: warning: `REG_EXTENDED' redefined
/usr/include/regex.h:47: warning: this is the location of the previous definition
../../regex/regex.h:32: warning: `REG_ICASE' redefined
/usr/include/regex.h:49: warning: this is the location of the previous definition
../../regex/regex.h:33: warning: `REG_NOSUB' redefined
/usr/include/regex.h:50: warning: this is the location of the previous definition
../../regex/regex.h:34: warning: `REG_NEWLINE' redefined
/usr/include/regex.h:48: warning: this is the location of the previous definition
../../regex/regex.h:42: warning: `REG_BADPAT' redefined
/usr/include/regex.h:81: warning: this is the location of the previous definition
../../regex/regex.h:43: warning: `REG_ECOLLATE' redefined
/usr/include/regex.h:69: warning: this is the location of the previous definition
../../regex/regex.h:44: warning: `REG_ECTYPE' redefined
/usr/include/regex.h:80: warning: this is the location of the previous definition
../../regex/regex.h:45: warning: `REG_EESCAPE' redefined
/usr/include/regex.h:70: warning: this is the location of the previous definition
../../regex/regex.h:50: warning: `REG_BADBR' redefined
/usr/include/regex.h:82: warning: this is the location of the previous definition
../../regex/regex.h:51: warning: `REG_ERANGE' redefined
/usr/include/regex.h:77: warning: this is the location of the previous definition
../../regex/regex.h:52: warning: `REG_ESPACE' redefined
/usr/include/regex.h:78: warning: this is the location of the previous definition
../../regex/regex.h:53: warning: `REG_BADRPT' redefined
/usr/include/regex.h:79: warning: this is the location of the previous definition
../../regex/regex.h:64: warning: `REG_NOTBOL' redefined
/usr/include/regex.h:62: warning: this is the location of the previous definition
../../regex/regex.h:65: warning: `REG_NOTEOL' redefined
/usr/include/regex.h:63: warning: this is the location of the previous definition
In file included from browscap.c:22:
../../php_regex.h:6: warning: `_REGEX_H' redefined
/usr/include/regex.h:7: warning: this is the location of the previous definition
In file included from ../../php_regex.h:5,
                 from browscap.c:22:
../../regex/regex.h:15: warning: redefinition of `regoff_t'
/usr/include/regex.h:23: warning: `regoff_t' previously declared here
../../regex/regex.h:21: conflicting types for `regex_t'
/usr/include/regex.h:37: previous declaration of `regex_t'
../../regex/regex.h:25: conflicting types for `regmatch_t'
/usr/include/regex.h:44: previous declaration of `regmatch_t'
../../regex/regex.h:29: conflicting types for `regcomp'
/usr/include/regex.h:102: previous declaration of `regcomp'
../../regex/regex.h:59: conflicting types for `regerror'
/usr/include/regex.h:104: previous declaration of `regerror'
../../regex/regex.h:63: conflicting types for `regexec'
/usr/include/regex.h:103: previous declaration of `regexec'
../../regex/regex.h:73: conflicting types for `regfree'
/usr/include/regex.h:105: previous declaration of `regfree'
make[2]: *** [browscap.o] Error 1
make[2]: Leaving directory `/home/campbell/tmp/php-4.0b1/ext/standard'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/campbell/tmp/php-4.0b1/ext'
make: *** [all-recursive] Error 1