As discussed in #2725, this commit renames a number of stacksize constants to
better convey their intended usage. In addition, constants for thread priority
are given a `THREAD_` prefix. Changes are:
* KERNEL_CONF_STACKSIZE_PRINTF renamed to THREAD_EXTRA_STACKSIZE_PRINTF
* KERNEL_CONF_STACKSIZE_DEFAULT renamed to THREAD_STACKSIZE_DEFAULT
* KERNEL_CONF_STACKSIZE_IDLE renamed to THREAD_STACKSIZE_IDLE
* KERNEL_CONF_STACKSIZE_MAIN renamed to THREAD_STACKSIZE_MAIN
* Move thread stacksizes from kernel.h to thread.h, since the prefix changed
* PRIORITY_MIN renamed to THREAD_PRIORITY_MIN
* PRIORITY_IDLE renamed to THREAD_PRIORITY_IDLE
* PRIORITY_MAIN renamed to THREAD_PRIORITY_MAIN
* Move thread priorities from kernel.h to thread.h since the prefix has changed
* MINIMUM_STACK_SIZE renamed to THREAD_STACKSIZE_MINIMUM for consistency
With many open PRs that could benefit from loading SDKs when needed,
instead adding vast amounts of code to RIOTs master, this PR provides
the "functions" `$(DOWNLOAD_TO_STDOUT)`, `$(DOWNLOAD_TO_FILE)`, and
`$(UNZIP_HERE)`.
The first "function" takes one argument, the URL from where to download
the content. It is then piped to stdout. To be used e.g. with `tar xz`.
The second "function" taken two arguments, the destination file name,
and the source URL. If the previous invocation was interrupted, then the
download gets continued, if possible.
The last "function" takes one argument, the source ZIP file. The file
gets extracted into the cwd, so best use this "function" with
`cd $(SOME_WHERE) &&`.
The clumsy name `$(UNZIP_HERE)` is taken because the program "unzip"
takes the environment variable `UNZIP` as the source file, even if
another file name was given on the command line. The rationale for that
is that the hackers of "unzip" hate their users. Also they sacrifice
hamsters to Satan.
