Here is an example of a configuration .ac file:
enable_mpi="yes"
enable_mpi_io="yes"
with_mpi_prefix="/path/to/mpi"
enable_64bit_flags="yes"
AR=ar
FC="mpif90"
CC="mpicc"
CXX="mpicxx"
with_fft_flavor="fftw3"
with_fft_libs="-L/path/to/fftw3/lib -lfftw3 -lfftw3f"
with_fft_incs="-I/path/to/fftw3/include"
with_linalg_flavor="mkl"
with_linalg_libs="-L/path/to/mkl/lib -Wl,--start-group -lmkl_intel_lp64 -lmkl_sequential -lmkl_core -Wl,--end-group -lpthread -lm"
with_linalg_incs="-I/path/to/mkl/include"
with_dft_flavor="libxc"
enable_clib="yes"
enable_gw_dpc="yes"