cpu/arm/k60: Removed custom C compile rules.

No reason to have custom rules when they are not different from the
default rules in Makefile.include.

The original Makefile.include rules are even better because they handle
dependency generation better.

Added missing CUSTOM_RULE_LINK to Makefile.k60 as well.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
cpu/arm/k60: Move platform specific upload commands.

Moved Mulle specific commands to platform/mulle/Makefile.mulle

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
C++: Add C++ support to the build system.

This still requires some more modifications to any custom startup code
in order to handle static/global constructors and destructors as well
as some minor support functions used by the compiler auto-generated
code.

See the cpu/arm/k60/cppsupport.cpp in the next future commit for
some guidelines for the supporting functions.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
cpu/arm/k60: Add C++ support.

This should be enough to support custom classes and objects, both
global and local.

Might need some changes to LDFLAGS if using new/delete in C++.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
C++: Add rules for building .cpp files.

Added default rules for building .cpp files using the C++ compiler.
Linking is still done using the C compiler, which is fine unless using
STL stuff (in that case you need to specify -lstdc++ or similar).

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>