termux_step_configure_haskell_build() {
	termux_setup_jailbreak_cabal
	printf "%s" "Jailbreaking Cabal file..."
	jailbreak-cabal "${TERMUX_PKG_SRCDIR}"/*.cabal && echo "done." || {
		termux_error_exit "failed."
	}

	ENABLE_SHARED="--enable-shared"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--disable-shared/}" ]; then
		ENABLE_SHARED=""
	fi

	DYNAMIC_EXECUTABLE="
	--ghc-options=-dynamic
	--enable-executable-dynamic
	--disable-library-vanilla
	"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--disable-executable-dynamic/}" ]; then
		DYNAMIC_EXECUTABLE=""
	fi

	HOST_FLAG="--host=$TERMUX_HOST_PLATFORM"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--host=/}" ]; then
		HOST_FLAG=""
	fi

	LIBEXEC_FLAG="--libexecdir=$TERMUX_PREFIX/libexec"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--libexecdir=/}" ]; then
		LIBEXEC_FLAG=""
	fi

	QUIET_BUILD=
	if [ "$TERMUX_QUIET_BUILD" = true ]; then
		QUIET_BUILD="-v0"
	fi

	LIB_STRIPPING="--enable-library-stripping"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--disable-library-stripping=/}" ] || [ "$TERMUX_DEBUG_BUILD" = "true" ]; then
		LIB_STRIPPING=""
	fi

	EXECUTABLE_STRIPPING="--enable-executable-stripping"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--disable-executable-stripping=/}" ] || [ "$TERMUX_DEBUG_BUILD" = "true" ]; then
		EXECUTABLE_STRIPPING=""
	fi

	SPLIT_SECTIONS="--enable-split-sections"
	if [ "$TERMUX_PKG_EXTRA_CONFIGURE_ARGS" != "${TERMUX_PKG_EXTRA_CONFIGURE_ARGS/--disable-split-sections=/}" ]; then
		SPLIT_SECTIONS=""
	fi

	# Avoid gnulib wrapping of functions when cross compiling. See
	# http://wiki.osdev.org/Cross-Porting_Software#Gnulib
	# https://gitlab.com/sortix/sortix/wikis/Gnulib
	# https://github.com/termux/termux-packages/issues/76
	AVOID_GNULIB=""
	AVOID_GNULIB+=" ac_cv_func_nl_langinfo=yes"
	AVOID_GNULIB+=" ac_cv_func_calloc_0_nonnull=yes"
	AVOID_GNULIB+=" ac_cv_func_chown_works=yes"
	AVOID_GNULIB+=" ac_cv_func_getgroups_works=yes"
	AVOID_GNULIB+=" ac_cv_func_malloc_0_nonnull=yes"
	AVOID_GNULIB+=" ac_cv_func_posix_spawn=no"
	AVOID_GNULIB+=" ac_cv_func_posix_spawnp=no"
	AVOID_GNULIB+=" ac_cv_func_realloc_0_nonnull=yes"
	AVOID_GNULIB+=" am_cv_func_working_getline=yes"
	AVOID_GNULIB+=" gl_cv_func_dup2_works=yes"
	AVOID_GNULIB+=" gl_cv_func_fcntl_f_dupfd_cloexec=yes"
	AVOID_GNULIB+=" gl_cv_func_fcntl_f_dupfd_works=yes"
	AVOID_GNULIB+=" gl_cv_func_fnmatch_posix=yes"
	AVOID_GNULIB+=" gl_cv_func_getcwd_abort_bug=no"
	AVOID_GNULIB+=" gl_cv_func_getcwd_null=yes"
	AVOID_GNULIB+=" gl_cv_func_getcwd_path_max=yes"
	AVOID_GNULIB+=" gl_cv_func_getcwd_posix_signature=yes"
	AVOID_GNULIB+=" gl_cv_func_gettimeofday_clobber=no"
	AVOID_GNULIB+=" gl_cv_func_gettimeofday_posix_signature=yes"
	AVOID_GNULIB+=" gl_cv_func_link_works=yes"
	AVOID_GNULIB+=" gl_cv_func_lstat_dereferences_slashed_symlink=yes"
	AVOID_GNULIB+=" gl_cv_func_malloc_0_nonnull=yes"
	AVOID_GNULIB+=" gl_cv_func_memchr_works=yes"
	AVOID_GNULIB+=" gl_cv_func_mkdir_trailing_dot_works=yes"
	AVOID_GNULIB+=" gl_cv_func_mkdir_trailing_slash_works=yes"
	AVOID_GNULIB+=" gl_cv_func_mkfifo_works=yes"
	AVOID_GNULIB+=" gl_cv_func_mknod_works=yes"
	AVOID_GNULIB+=" gl_cv_func_realpath_works=yes"
	AVOID_GNULIB+=" gl_cv_func_select_detects_ebadf=yes"
	AVOID_GNULIB+=" gl_cv_func_snprintf_posix=yes"
	AVOID_GNULIB+=" gl_cv_func_snprintf_retval_c99=yes"
	AVOID_GNULIB+=" gl_cv_func_snprintf_truncation_c99=yes"
	AVOID_GNULIB+=" gl_cv_func_stat_dir_slash=yes"
	AVOID_GNULIB+=" gl_cv_func_stat_file_slash=yes"
	AVOID_GNULIB+=" gl_cv_func_strerror_0_works=yes"
	AVOID_GNULIB+=" gl_cv_func_strtold_works=yes"
	AVOID_GNULIB+=" gl_cv_func_symlink_works=yes"
	AVOID_GNULIB+=" gl_cv_func_tzset_clobber=no"
	AVOID_GNULIB+=" gl_cv_func_unlink_honors_slashes=yes"
	AVOID_GNULIB+=" gl_cv_func_unlink_honors_slashes=yes"
	AVOID_GNULIB+=" gl_cv_func_vsnprintf_posix=yes"
	AVOID_GNULIB+=" gl_cv_func_vsnprintf_zerosize_c99=yes"
	AVOID_GNULIB+=" gl_cv_func_wcrtomb_works=yes"
	AVOID_GNULIB+=" gl_cv_func_wcwidth_works=yes"
	AVOID_GNULIB+=" gl_cv_func_working_getdelim=yes"
	AVOID_GNULIB+=" gl_cv_func_working_mkstemp=yes"
	AVOID_GNULIB+=" gl_cv_func_working_mktime=yes"
	AVOID_GNULIB+=" gl_cv_func_working_strerror=yes"
	AVOID_GNULIB+=" gl_cv_header_working_fcntl_h=yes"
	AVOID_GNULIB+=" gl_cv_C_locale_sans_EILSEQ=yes"

	LLVM_BACKEND=""
	[ "${TERMUX_ARCH}" != "i686" ] && {
		LLVM_BACKEND="-fllvm --ghc-option=-fllvm"
	}
	[ "$TERMUX_DEBUG_BUILD" = "true" ] && OPTIMISATION="-O0" || OPTIMISATION="-O"

	# Some packages rely on cabal build, therefore they may not have Setup.hs, (though very rare case)
	# as cabal has that configured by default.
	if [ ! -f "${TERMUX_PKG_SRCDIR}/Setup.hs" ] && [ ! -f "${TERMUX_PKG_SRCDIR}/Setup.lhs" ]; then
		echo "Warning: No Setup.{hs,lhs} file found in ${TERMUX_PKG_SRCDIR}."
		echo "Using default Setup.hs..."
		cp "${TERMUX_SCRIPTDIR}/scripts/build/haskell-build/default-setup.hs" "${TERMUX_PKG_SRCDIR}/Setup.hs"
	fi

	# NOTE: We do not want to quote AVOID_GNULIB as we want word expansion.
	# shellcheck disable=SC2086
	env $AVOID_GNULIB runhaskell Setup configure \
		$OPTIMISATION \
		--prefix=$TERMUX_PREFIX \
		--configure-option=--disable-rpath \
		--configure-option=--disable-rpath-hack \
		--configure-option=--host=$HOST_FLAG \
		--ghc-option=-optl-Wl,-rpath=$TERMUX_PREFIX/lib \
		--ghc-option=-optl-Wl,--enable-new-dtags \
		--with-compiler=$(command -v termux-ghc) \
		--with-ghc-pkg=$(command -v termux-ghc-pkg) \
		--with-hsc2hs=$(command -v termux-hsc2hs) \
		--hsc2hs-option=--cross-compile \
		--with-ld=$LD \
		--with-strip=$STRIP \
		--with-ar=$AR \
		--with-pkg-config=$PKG_CONFIG \
		--with-happy=$(command -v happy) \
		--with-alex=$(command -v alex) \
		--with-runghc=$(command -v runghc) \
		--extra-include-dirs=$TERMUX_PREFIX/include \
		--extra-lib-dirs=$TERMUX_PREFIX/lib \
		--disable-tests \
		$LLVM_BACKEND \
		$SPLIT_SECTIONS \
		$EXECUTABLE_STRIPPING \
		$LIB_STRIPPING \
		$TERMUX_PKG_EXTRA_CONFIGURE_ARGS \
		$ENABLE_SHARED \
		$QUIET_BUILD \
		$LIBEXEC_FLAG \
		$DYNAMIC_EXECUTABLE
}