set -eu

ERTS_INCLUDE_DIR=${ERTS_INCLUDE_DIR:-$(erl -noshell -s init stop -eval "io:format(\"~s/erts-~s/include/\", [code:root_dir(), erlang:system_info(version)]).")}
CC=${CC:-cc}
CFLAGS="-fPIC -I${ERTS_INCLUDE_DIR} -std=gnu11 \
  -Wall -Wextra -Wno-missing-field-initializers \
  -O3 ${CFLAGS:--march=native -mtune=native -ggdb}"
LDFLAGS=${LDFLAGS:-}
if [ "$(uname -s)" = Darwin ]; then
    LDFLAGS="$LDFLAGS -flat_namespace -undefined suppress"
fi

SRC=./c_src
BUILD=./build
IMPLEMENTATIONS="xorshift pcg32"

mkdir -p $BUILD

test_for_rdrand() {
    "$CC" -O -o $BUILD/test_for_rdrand $SRC/test_for_rdrand.c && $BUILD/test_for_rdrand
}

if test_for_rdrand 2>/dev/null; then
    CFLAGS="$CFLAGS -DHAVE_RDRAND"
    IMPLEMENTATIONS="$IMPLEMENTATIONS rdrand"
fi