php编译exif.so，解决Call to undefined exif_imagetype()报错

如果php是编译安装，找到或重新下载源码，进到exif目录，比如 /usr/tmp/php-7.2.1/ext/exif

/usr/local/php/bin/phpize
./configure --with-php-config=/usr/local/php/bin/php-config
make && make install

然后vim 编辑php.ini 添加启用扩展

vim /usr/local/php/etc/php.ini
;extension=mbstring
extension=exif