Due to the way the headers are organized a single change in a
AP_GPS backend would trigger a rebuild for most of the files in the
project. Time could be saved by using ccache (since most of the things
didn't change) but we can do better, i.e. re-organize
the headers so we don't have to re-build everything.
This makes internal headers internal and then other libraries only
depend on the AP_GPS.h header.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
Lucas De Marchi
Gustavo Jose de Sousa
Andrew Tridgell
Holger Steinhaus