def readBuildVariants(file_path):
    """Reads variants file and returns a list of the variants to build.

    Args:
        file_path (string): Path to the variants file.

    Returns:
        list: Returns a list containing each variant listed in the variants
            file.

    """
    with open(file_path, 'r') as variant_file:
        variant_data = variant_file.readlines()

    variants = []
    for line in variant_data:
        if line.startswith('VARIANTS :='):
            variants.extend(line.split()[2:])

    variants = [variant + '.mk' for variant in variants]
    return variants