warning: `MCRYPT_FAILED' redefined

I am having trouble compiling the CGI version of PHP. Compiling PHP as a DSO module works but I run into trouble when I remove the --with-apxs configure option. I compared the output of configure when building the DSO module and CGI module. Most of the differences make sense except the difference in 'checking for init_mcrypt'. When configuring the DSO the answer is YES and for CGI it is NO. Why is configure being inconsistent? The relevant archives I am using: php-4.0.3pl1.tar.gz libmcrypt-2.4.6.tar.gz The error messages: mcrypt.c:222: warning: `MCRYPT_FAILED' redefined /usr/include/mcrypt.h:30: warning: this is the location of the previous definition mcrypt.c: In function `php_minit_mcrypt': mcrypt.c:260: `MCRYPT_BLOWFISH_448' undeclared (first use in this function) mcrypt.c:260: (Each undeclared identifier is reported only once mcrypt.c:260: for each function it appears in.) mcrypt.c:261: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:262: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:263: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:264: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:265: `MCRYPT_SAFER_64' undeclared (first use in this function) mcrypt.c:266: `MCRYPT_SAFER_128' undeclared (first use in this function) mcrypt.c:267: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:268: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:269: `MCRYPT_RC2_1024' undeclared (first use in this function) mcrypt.c:270: `MCRYPT_TWOFISH_128' undeclared (first use in this function) mcrypt.c:271: `MCRYPT_TWOFISH_192' undeclared (first use in this function) mcrypt.c:272: `MCRYPT_TWOFISH_256' undeclared (first use in this function) mcrypt.c:273: `MCRYPT_BLOWFISH_128' undeclared (first use in this function) mcrypt.c:274: `MCRYPT_BLOWFISH_192' undeclared (first use in this function) mcrypt.c:275: `MCRYPT_BLOWFISH_256' undeclared (first use in this function) mcrypt.c:276: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:277: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:278: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:279: `MCRYPT_SERPENT_128' undeclared (first use in this function) mcrypt.c:280: `MCRYPT_SERPENT_192' undeclared (first use in this function) mcrypt.c:281: `MCRYPT_SERPENT_256' undeclared (first use in this function) mcrypt.c:282: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:283: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:284: warning: passing arg 3 of `zend_register_long_constant' makes integer from pointer without a cast mcrypt.c:285: `MCRYPT_RC2_256' undeclared (first use in this function) mcrypt.c:286: `MCRYPT_RC2_128' undeclared (first use in this function) mcrypt.c:287: `MCRYPT_RC6_256' undeclared (first use in this function) mcrypt.c:288: `MCRYPT_IDEA' undeclared (first use in this function) mcrypt.c:289: `MCRYPT_RC6_128' undeclared (first use in this function) mcrypt.c:290: `MCRYPT_RC6_192' undeclared (first use in this function) mcrypt.c:291: `MCRYPT_RC4' undeclared (first use in this function) mcrypt.c: In function `php_if_mcrypt_get_cipher_name': mcrypt.c:1500: warning: assignment makes pointer from integer without a cast make[3]: *** [mcrypt.lo] Error 1 make[3]: Leaving directory `/usr/local/src/php-4.0.3pl1/ext/mcrypt' make[2]: *** [all-recursive] Error 1 make[2]: Leaving directory `/usr/local/src/php-4.0.3pl1/ext/mcrypt' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/usr/local/src/php-4.0.3pl1/ext' make: *** [all-recursive] Error 1 Difference in configure output: < DSO > CGI 37c37,38 < checking for Apache module support via DSO through APXS... yes --- > checking for Apache module support via DSO through APXS... no > checking for Apache module support... no 38a40,41 > checking whether to force Apache CGI redirect... no > checking whether to discard path_info + path_translated... no 47c50 < checking for chosen SAPI module... apache --- > checking for chosen SAPI module... cgi 242c245 < checking for init_mcrypt in -lmcrypt... no --- > checking for init_mcrypt in -lmcrypt... yes 377,378c380,381 < checking whether to build shared libraries... yes < checking whether to build static libraries... no --- > checking whether to build shared libraries... no > checking whether to build static libraries... yes 383a387,415 > Configuring shared libtool > loading cache ./config.cache within ltconfig > checking host system type... i686-pc-linux-gnu > checking for ranlib... ranlib > checking for gcc... gcc > checking whether we are using GNU C... yes > checking for object suffix... o > checking for executable suffix... (cached) no > checking for gcc option to produce PIC... -fPIC > checking if gcc PIC flag -fPIC works... yes > checking if gcc supports -c -o file.o... yes > checking if gcc supports -c -o file.lo... yes > checking if gcc supports -fno-rtti -fno-exceptions ... yes > checking if gcc static flag -static works... -static > checking whether ln -s works... yes > checking for ld used by GCC... /usr/bin/ld > checking if the linker (/usr/bin/ld) is GNU ld... yes > checking whether the linker (/usr/bin/ld) supports shared libraries... yes > checking for BSD-compatible nm... /usr/bin/nm -B > checking command to parse /usr/bin/nm -B output... ok > checking how to hardcode library paths into programs... immediate > checking for /usr/bin/ld option to reload object files... -r > checking dynamic linker characteristics... Linux ld.so > checking if libtool supports shared libraries... yes > checking whether to build shared libraries... yes > checking whether to build static libraries... no > checking for objdir... .libs > creating shlibtool > 421c453 < creating sapi/apache/Makefile --- > creating sapi/cgi/Makefile