Configure: error: mcrypt.h Not Found. Please Reinstall libmcrypt

Issue

While compiling PHP from source on CentOS server, we get the error below:

checking for mcrypt support... yes
configure: error: mcrypt.h not found. Please reinstall libmcrypt.

The root of the problem is we’ve enabled this option –with-mcrypt.

./configure --prefix=/usr/local/php7 \
    --with-config-file-path=/usr/local/php7/etc \
    --with-config-file-scan-dir=/usr/local/php7/etc/conf.d \
    --enable-bcmath \
    ...
    --with-mcrypt \
    --with-jpeg-dir

Solution

In this, we have to install the dependencies packages as follows:

sudo yum -y install libmcrypt-devel

# yum list installed | grep libmcrypt
libmcrypt.x86_64                     2.5.8-13.el7                   @epel
libmcrypt-devel.x86_64               2.5.8-13.el7                   @epel

And then try to re-compile PHP from source and it should be able to compile this time.