Update configure.php comments, add SPDX Identifier
Update configure.php comments, add SPDX Identifier

C89 commenting updates to align with Linux kernel coding style, Chapter 8 https://www.kernel.org/doc/Documentation/CodingStyle
mkdolan/facade,brianwarner/facade,brianwarner/facade,mkdolan/facade,mkdolan/facade,brianwarner/facade