7.2编译php成功。8.1就是不行！

./configure --prefix=/usr/local/php --with-apxs2=/usr/local/apache/bin/apxs --with-mysql=/usr/local/mysql --disable-debug --with-libxml-dir --enable-mbstring --with-gd --enable-gd-jis-conv --enable-gd-native-ttf --with-freetype-dir --with-jpeg-dir --with-png-dir --with-zlib

（php-5.2.5）
之前pkg_add pkg-config-0.22_1.tbz；pkg_add libxml2-2.6.30.tbz；pkg_add gd-2.0.35,1.tbz
7.2下没问题！

8.1下
./configure --prefix=/usr/local/php --with-apxs2=/usr/local/apache/bin/apxs --with-mysql=/usr/local/mysql --disable-debug --with-libxml-dir --enable-mbstring --with-gd --enable-gd-jis-conv --enable-gd-native-ttf --with-freetype-dir --with-jpeg-dir --with-png-dir --with-zlib

checking whether to enable LIBXML support... yes
checking libxml2 install dir... yes
checking for xml2-config path... /usr/local/bin/xml2-config
checking whether libxml build works... no

（换成php-5.3.3后 问题依旧）

checking whether libxml build works... no