declared but undefined functions

[Trevor Jim]

I notice that the following functions:

   flockfile
   ftrylockfile
   funlockfile
   pclose
   popen
   execvp
   getcwd

are declared by newlib headers but are not actually
defined when I configure with --target=arm-elf.

(I notice because I have a tool that crawls the
headers and generates some code based on what
is declared there.)

It seems that the functions should either not be
declared, or should be defined.

Of course, for my purposes I can just supply dummy
definitions of the missing functions, and that's
what I've done.

Thanks for newlib!

-Trevor