- XCode project
- Scons :
    scons stopped working for Os X in the last month (dont know when) :
     * the '.' and '..' keywords in CCPPATH
          are not recognized anymore for sconscripts compiling files at
          a sub level
     * when doing a scons clean, the 3 subdirs in build dir are removed
      and scons then fail to recreate them (exten, intern, source)
this commit solve the first problem as a temp workaround
for the latter simply recreate the dirs manually
I will investigate that further when on vacations,  which i should already
 be.
 ;(
all 3 build systems are now working on Os X