R CMD rtags outputs "-n" if xpg_echo is on.
/bin/sh of Mac OS X enable xpg_echo by default, so R CMD rtags output "-n" when executed on Mac OS X.
To fix this issue, "echo -n" should be replaced with "printf".
I attached the patch.
Created attachment 1417 [details]
replace "echo -n" with "printf"
printf is not portable.
There are options in configure for this (use echo ...\c for XSI-conformant systems'. Changed in R-devel.