The face recognition for the nextcloud into centos 7 need DLib and OpenBLAS.
The problem is that DLib require C++11 support and the centos 7 have older version of gcc the solution is to install
yum install centos-release-scl
yum install devtoolset-7
The path for the gcc is located /opt/rh/devtoolset-7/root/usr/bin/gcc
To build the DLib this command
cmake -DBUILD_SHARED_LIBS=ON ..
Need to be replaced with
cmake -D CMAKE_C_COMPILER=/opt/rh/devtoolset-7/root/usr/bin/gcc -D CMAKE_CXX_COMPILER=/opt/rh/devtoolset-7/root/usr/bin/g++ -DBUILD_SHARED_LIBS=ON ..
Also to install the pdlib the ./configure need to be replaced with
PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig CC=/opt/rh/devtoolset-7/root/usr/bin/gcc CXX=/opt/rh/devtoolset-7/root/usr/bin/g++ ./configure
