-give the --with-gmp=PATH option to the `configure'. The PATH is the path
-to the GMP library in your system.
+give the --with-gmp[=DIR] option to the `configure'. The DIR is the upper
+path in your system which contains lib/ and include/ for GMP library.
+ Note that MPI is the prefered arbitrary precision arithmetic library and
+GMP can be used as a fall-back if you have problems with the MPI library
+included within this package.
+
+`--with-iconv[=DIR]'
+
+ If your system doesn't provide iconv() function in its native libraries
+(usually libc) or if this function is broken (e.g. older Solaris systems),
+you may want to use libiconv instead. The DIR is the upper path in your
+system which contains lib/ and include/ for libiconv (e.g. /usr/local).