These warnings fix a class of warnings that I saw during CI checks for macOS sim builds. For example:
devif/devif_callback.c:111:49: warning: for loop has empty body [-Wempty-body]
prev = curr, curr = curr->nxtdev);
^
devif/devif_callback.c:111:49: note: put the semicolon on a separate line to silence this warning
I did not put the semi-colon on a separate line, but used braces.
PR #488 introduced an error in a file license header in file sched/mqueue/mqueue.h. This commit fixe that error and in the course of doing that, changing the license header to the standard Apache 2.0 header. I am the author and copyright hold of all modified files.
Change all calls to mq_receive() and mq_timedreceive() in the OS to calls to nxmq_receive() and nxmq_timedreceive(), making appropriate changes for differences in return values.
sched/mqueue: Add nxmq_receive() and mxmq_timedreceive() which are functionally equivalent to the standard mq_receive and mq_timedreceive() except that (1) they do not create cancellation points, and (2) the do not modify the application's errno variable.
sched/mqueue: Rename all private static functions for use the nxmq_ vs. mq_ naming.
sched/mqueue: Rename all OS internal functions declared in sched/mqueue/mqueue.h to begin with nxmq_ vs. mq_. The mq_ prefix is reserved for standard application interfaces.
