Update ofSystemUtils.cpp

changes so master can build on ARM LINUX
Update ofSystemUtils.cpp

TARGET_LINUX_ARM-> TARGET_RASPBERRY_PI
Merge pull request #2988 from danthemellowman/patch-8

Update ofSystemUtils.cpp

Just tested this and it allows the RPi to compile again. It won't effect any other platforms so merging
smaller fix for RPi compiling issue with XInitThreads
smaller fix for RPi not being able to compile with XInitThreads
permissions fix
remove RPi ifdefs