configure.ac: update macros format, use AX_CHECK_COMPILE_FLAG instead of custom test
configure.ac: update macros format, use AX_CHECK_COMPILE_FLAG instead of custom test
slackner/libmicrohttpd,pmq20/libmicrohttpd,pmq20/libmicrohttpd,pmq20/libmicrohttpd,slackner/libmicrohttpd,slackner/libmicrohttpd