Only do trick when enabled, check neg as well as pos NA/NaN
make function ptr use conform to C99
Merge branch '02-evalv-prim' into 03
Merge branch '02-evalv-prim' into 03-ISNAN
put in missing return in Rf_eval
remove unused variables
Merge branch '02-evalv-prim' into 03
Merge branch '02-promiseWith' into 03
Merge branch '03' into 03-ISNAN