gmp NM autoconf binary

In configure.ac nm for gmp is "hardwired". This imposes a problem (especially on OSX). The right way seems to be inferring nm from the autoconf (ie removing this assignment NM=nm). I remember there was some problem with this when cross-compiling, hence this direct assignment, but this needs to be addressed, tested and fixed.

diff --git a/src/configure b/src/configure
index f151f8d..fed3ed3 100755
--- a/src/configure
+++ b/src/configure
@@ -5628,7 +5628,8 @@ $as_echo "$as_me: Configuring included GMP 
library:" >&6;}
    fi
    mkdir gmp
      (destdir=`${PWDCMD}`; cd gmp && CC="${CC} ${PICFLAG}" \
-     NM=nm $srcdir/gmp/configure --disable-shared --prefix=${destdir} \
+ NM=$PLATFORM_PREFIX/bin/arm-linux-androideabi-nm \
+                                      $srcdir/gmp/configure 
--disable-shared --prefix=${destdir} \
       -infodir=${destdir}/doc --includedir=${destdir}/ecl --with-pic \
       --libdir=${destdir} --build=${gmp_build} --host=${host_alias} \
       CFLAGS="$CFLAGS" LDFLAGS="$LDFLAGS" CPPFLAGS="$CPPFLAGS" 
CC="${CC} ${PICFLAG}"