Thank you for your input. How about the following?
You may also use the --cflags and --ldflags options to pass additional parameters to the compiler and linker, respectively; they
are frequently used to pass -I and -L flags to specify supplementary include and library directories. If a directory name includes spaces, you will need to enclose it in quotes, as follows -I"C:/Program Files/GnuTLS-2.10.1/include". Note that the directory
name is enclosed in quotes, not the entire argument. Also note that this functionality is only supported if command extensions are available. If command extensions are disabled and you attempt to use this functionality you may see the following warning message "Error
in --cflags argument: ... Backslashes and quotes cannot be used with --cflags. Please use forward slashes for filenames and paths (e.g. when passing directories to -I)."