Snow Leopard 10.6.7, Xcode 4.0.1:

$ cd nginx-1.0.6
$ ./configure --prefix=/usr/local --with-cc-opt="-I/usr/local/include -O2 -Wno-deprecated-declarations" --with-ld-opt="-L/usr/local/lib" --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx/nginx.pid --lock-path=/var/run/nginx/nginx.lock --http-client-body-temp-path=/var/run/nginx/client_body_temp --http-proxy-temp-path=/var/run/nginx/proxy_temp --http-fastcgi-temp-path=/var/run/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/run/nginx/uwsgi_temp --with-http_dav_module --with-http_flv_module --with-mail --with-http_ssl_module --with-mail_ssl_module --with-http_stub_status_module --with-ipv6 --with-http_perl_module --with-perl=/usr/bin/perl --with-http_realip_module --with-http_addition_module --with-http_sub_module --with-http_gzip_static_module

$ make
...
gcc -c -pipe -O -W -Wall -Wpointer-arith -Wno-unused-parameter -Wunused-function -Wunused-variable -Wno-unused-value -Werror -g -I/usr/local/include -O2 -Wno-deprecated-declarations -arch x86_64 -arch i386 -arch ppc -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -I/usr/local/include -I/System/Library/Perl/5.10.0/darwin-thread-multi-2level/CORE -I src/core -I src/event -I src/event/modules -I src/os/unix -I /opt/local/include -I objs -I src/http -I src/http/modules -I src/http/modules/perl \
-o objs/src/http/modules/perl/ngx_http_perl_module.o \
src/http/modules/perl/ngx_http_perl_module.c
In file included from src/http/modules/perl/ngx_http_perl_module.h:17,
from src/http/modules/perl/ngx_http_perl_module.c:10:
/System/Library/Perl/5.10.0/darwin-thread-multi-2level/CORE/perl.h:3240: error: expected specifier-qualifier-list before ‘bool’
...

Seems to be a know issue in other contexts.