[MPFR] Mac OS X power pc issue with C99

[paul zimmermann]

       Dear Arnold,

the "duplicate symbol ___gmpz_abs" seems to be a frequent issue on Mac OS:

http://mail-index.netbsd.org/pkgsrc-users/2008/11/20/msg008688.html
https://groups.google.com/forum/#!topic/sage-devel/LVASCTPZnXw
http://avr.2057.n7.nabble.com/Trouble-compiling-avr-gcc-gt-4-4-4-on-Mac-OS-X-Leopard-with-gcc-4-2-td8706i20.html

The most useful answer I found is that one:

https://gmplib.org/list-archives/gmp-bugs/2010-January/001747.html

Hope this helps,
Paul Zimmermann