PHP_ARG_ENABLE(arma,           for armadillo support,
[  --enable-arma            Enable armadillo support])

PHP_ARG_ENABLE(arma-operators, for operator overloading support in armadillo,
[  --enable-arma-operators  Enable operator overloading for armadillo ], no, no)

PHP_ARG_ENABLE(arma-pch,       build PCH header of armadillo,
[  --enable-arma-pch        Enable building PCH header of armadillo ], no, no)

if test "$PHP_ARMA" != "no"; then
  PHP_REQUIRE_CXX()

  # If enabled, try building pre-compiled header for armadillo.
  if test "$PHP_ARMA_PCH" != "no"; then
    CXX_INCLEDE_PATHS=($(echo | $CXX -xc++ -E -v - 2>&1 | grep -e '^ /\S*$'))
    PCH_FILE='./build/armadillo.gch'
    # Note that '-D' option is valid when compiling PCH header, but not when using it.
    PCH_COMPILE_FLAGS=(-std=c++17 -xc++-header -DARMA_DONT_PRINT_ERRORS -fPIC -g)
    if test "$PHP_DEBUG" != "0"; then
      PCH_COMPILE_FLAGS+=(-O0)
    else
      PCH_COMPILE_FLAGS+=(-O2)
    fi
  fi
  for POSSIBLE_INCLUDE_DIR in ${CXX_INCLEDE_PATHS[[@]]}; do
    ARMADILLO_HEADER_FILE=$POSSIBLE_INCLUDE_DIR/armadillo
    if test -f "$ARMADILLO_HEADER_FILE"; then
      $CXX ${PCH_COMPILE_FLAGS[[@]]} $ARMADILLO_HEADER_FILE -o $PCH_FILE
      break
    fi
  done

  # Include PCH file if valid.
  EXTRA_CXXFLAGS="-std=c++17 -DARMA_DONT_PRINT_ERRORS"
  CLANG_TEST_STR=`echo | $CXX -dM -E - | grep __clang__`
  if test -f "$PCH_FILE"; then
    if test -n "$CLANG_TEST_STR"; then
      EXTRA_CXXFLAGS+=" -include-pch $PCH_FILE"
    else
      DUMMY_ARMADILLO_HEADER_FILE='./build/armadillo'
      touch "$DUMMY_ARMADILLO_HEADER_FILE"
      EXTRA_CXXFLAGS+=" -include $DUMMY_ARMADILLO_HEADER_FILE"
    fi
    AC_DEFINE(PHP_ARMA_ENABLE_PCH, 1, [ Defined if using pre-compiled armadillo header. ])
  fi

  # Disable some clang warnings, which we don't care.
  if test -n "$CLANG_TEST_STR"; then
    EXTRA_CXXFLAGS+=' -Wno-undefined-var-template -Wno-deprecated-declarations'
  fi

  # Enable/disable operator overloading support.
  OPERATORS_SRC="src/operators.cc"
  ARMA_SRC=`ls -1d src/*.cc | grep -v $OPERATORS_SRC`
  if test "$PHP_ARMA_OPERATORS" != "no"; then
    AC_DEFINE(PHP_ARMA_OPERATORS, 1, [ Defined if operator overloading is enabled for armadillo. ])
    ARMA_SRC+=" $OPERATORS_SRC"
  fi

  PHP_NEW_EXTENSION(arma, $ARMA_SRC, $ext_shared, , $EXTRA_CXXFLAGS)

  PHP_ADD_LIBRARY(armadillo, 1, ARMA_SHARED_LIBADD)
  PHP_SUBST(ARMA_SHARED_LIBADD)
fi