[patch] add -nolibc option

[Joseph Myers]

On Thu, 7 Jun 2018, Olivier Hainque wrote:

> An updated version of the patch is attached, accounting for
> your two comments and expanding on the .texi documentation a
> bit. 

I see you're not changing LINK_GCC_C_SEQUENCE_SPEC in arc/elf.h.  That's a 
slightly odd case in that it isn't actually using %L, but is using -lc 
directly, whereas there's an empty definition of LIB_SPEC.

I'd expect the documentation to say something about libraries added only 
for particular languages by the front-end drivers (-lstdc++ -lm, 
-lgfortran -lm, etc.).  It may be that the option isn't particularly 
meaningful for code using such front-end drivers that add those libraries, 
because those libraries depend on libc (and code in those languages will 
generally depend on their libraries), but it should still say what the 
effects are.

-- 
Joseph S. Myers
joseph@codesourcery.com