Please see #1715.
Closes#1715.
This PR implements the new Makefile variables "FEATURES_PROVIDED" and
"FEATURES_REQUIRED". A board *can* have a new file `Makefile.features`
which looks like:
```make
FEATURES_PROVIDED = transceiver
```
An application can have a corresponding line
```make
FEATURES_REQUIRED = transceiver
```
If the selected BOARD does not fulfil the requirements of the
application, then a *warning* is issued at compile time.
This change only includes the feature "transceiver", further features
are expected to be listed in further PRs. The requirement "transceiver"
is automatically added if the application uses the module
"defaulttransceiver".
`make buildtest` understands the new feature listing, so the user won't
need to add boards to `BOARD_BLACKLIST` manually.
Part of the change are the added Make targets
* `info-features-missing`, which prints the required features
`\setminus` the provided features. The output is empty if there are no
features missing.
* `info-boards-features-missing`, the same as `info-features-missing`
but as a table for all boards, but heeded `BOARD_WHITELIST` and
`BOARD_BLACKLIST`.
Applications don't have to use this new feature. This change does not
break existing Makefile.
This PR converts tabs to white spaces.
The statement I used for the conversion:
'''find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;'''
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
Many modules have subdirectories. Often these subdirectories should only
be included under certain circumstances. Modules that use submodules
currently need to use this pattern:
```make
DIRS = …
all: $(BINDIR)$(MODULE).a
@for i in $(DIRS) ; do $(MAKE) -C $$i ; done ;
include $(RIOTBASE)/Makefile.base
clean::
@for i in $(DIRS) ; do $(MAKE) -C $$i clean ; done ;
```
This PR moves the `all:` and `clean::` boilerplate into `Makefile.base`.
We have sane defaults for `ELFFILE` and `HEXFILE` in the root
`Makefile.include`. The local definition for `ELFFILE` of mbed_lpc1768's
`Makefile.include` was wrong, which caused e.g. `make buildsize` to
fail.
Closes#993.
We do not need to descend into the modules to know what to do on
`make clean BOARD=blub`. We can just invoke `rm -rf bin/blub`.
This PR only keeps the descending into the USEPKGs, since they might
want to delete cached/downloaded/extracted data.
Creating all object files in one directory is bound to produce name
clashes. RIOT developers may take care to use unique file names, but
external packages surely don't.
With this change all the objects of a module (e.g. `shell`) will be
created in `bin/$(BOARD)/$(MODULE)`.
I compared the final linker command before and after the change. The
`.o` files (e.g. `startup.o`, `syscall.o` ...) are included in the same
order. Neglecting the changed path name where the `.o` files reside, the
linker command stays exactly the same.
A major problem could be third party boards, because the location of the
`startup.o` needs to the specified now in
`boards/$(BOARD)/Makefile.include`, e.g.
```Makefile
export UNDEF += $(BINDIR)msp430_common/startup.o
```
An application might want to use C11 features. The user would assume
that setting `CFLAGS=-std=gnu11` in the Makefile would work. It does not
since the board's Makefile.include shadows the `-std` flag.
This patch removes the `-std=gnu99` from the various Makefile.includes,
and sets the flag in the common Makefile.include of RIOT instead.
If an `-std` flag was provided by an earlier Makefile (the application,
the board, or the CPU [whilst only the former one should]), then no
additional flag is set. It is first tested if the supplied compiler
understands `-std=gnu99`, then `-std=c99`.
