any idea what could be causing this error when i add the -fvia-C option /tmp/ghc32300_0/ghc32300_0.hc:6:23: error: SFMT_wrap.h: No such file or directory make: *** [release] Error 1 I am also passing these options: -O2 -fexcess-precision -funbox-strict-fields -fglasgow-exts -fbang-patterns -lcblas Thanks, Anatoly