/bin/sh ../libtool --mode=compile c++ -DHAVE_CONFIG_H -I. -I. -I.. -I./inc -I../ -I../util -I../filter -I/usr/local/include -g -O2 -c readonly_ws.cc
c++ -DHAVE_CONFIG_H -I. -I. -I.. -I./inc -I../ -I../util -I../filter -I/usr/local/include -g -O2 -c readonly_ws.cc
readonly_ws.cc: In function `size_t page_size()':
readonly_ws.cc:124: `_SC_PAGESIZE' undeclared (first use this function)
readonly_ws.cc:124: (Each undeclared identifier is reported only once
readonly_ws.cc:124: for each function it appears in.)
make[3]: *** [readonly_ws.lo] Error 1

pspell installed without difficulty, but aspell dies during compile with the error you've quoted.

Help?

1. CHANGE lib/readonly_ws.cc as follows:

replace return sysconf (_SC_PAGESIZE);
with return getpagesize();

2. CHANGE filter/repl.cc as follows:

add:
#include "single_repl.hh"
#include "hash_repl-t.hh"
#include "substr_repl-t.hh"
#include "repl_func.hh"

replace: #include "hash_repl-p.hh"
with: //#include "hash_repl-p.hh"

3. run "configure" like this:
./configure --disable-curses

... that did it for me on Mac OS X Server 10.1.