search for: r_check_funcs

I was compiling R on a system which admittedly was in the odd situation that it declared a function in math.h, but didn't have the associated implementation in libm, and the R 2.15.1 compilation failed. It turns out that R_CHECK_FUNCS is rather less robust than the standard AC_CHECK_FUNCS which actually attempts to link. On my temporarily broken system, AC_CHECK_FUNCS would not have been fooled, and R would have compiled successfully. Thoughts on making R_CHECK_FUNCS simply an alias for AC_CHECK_FUNCS? Cheers, Patrick