Cannot build sed-4.1.1 with --disable-nls

[Lars Hecking]

I'm not sure whether the problem is in sed or gettext.

Solaris 9/SPARC
gcc 2.95.3
sed 4.1.1
gettext 0.14.1

$ tar xzf sed-4.1.1.tar.gz
$ cd sed-4.1.1
$ ./configure --disable-nls
...
$ make
...
Making all in sed
source='sed.c' object='sed.o' libtool=no \
depfile='.deps/sed.Po' tmpdepfile='.deps/sed.TPo' \
depmode=gcc /bin/bash ../config/depcomp \
gcc -DHAVE_CONFIG_H -I. -I. -I..  -I../lib -I../intl  -I.. -I../lib  
-DLOCALEDIR=\"/usr/local/share/locale\"    -g -O2 -c sed.c
In file included from /usr/include/locale.h:51,
                 from sed.c:49:
/usr/local/include/libintl.h:118: parse error before `const'
/usr/local/include/libintl.h:172: parse error before `const'
*** Error code 1

Why are gettext include files used even though I explicitly specified
--disable-nls?