enlightenment: disable ptrace for ppc & sparc

The sys/ptrace.h header for uclibc <= 0.9.33.2 is incomplete and lacks
required definitions for powerpc and sparc.
Fixes:
http://autobuild.buildroot.net/results/a7f/a7f95353f5592a9399c542d8d56c3ca040f8a61a/



Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>