missing libart includes on linux

[Ralf Habacker]

Hi, 

while testing kio on linux I recognized, that LIBART was detected 

cache/libart.cache.py

CACHED_LIBART = 1
CXXFLAGS_LIBART = ['-I/usr/include/libart-2.0']
LINKFLAGS_LIBART = ['-L/usr/lib', '-lart_lgpl_2', '-lm']

but is still missing, although obj.uselib='LIBART' is specificed. 

Any idea ?
Regards
 Ralf