can't build indent 2.2.9 from source

I'm trying to build indent 2.2.9 from source, but am getting compile errors:
source='output.c' object='output.o' libtool=no \
    depfile='.deps/output.Po' tmpdepfile='.deps/output.TPo' \
    depmode=gcc3 /bin/sh ../config/depcomp \
    gcc -DHAVE_CONFIG_H -DLOCALEDIR=\"/usr/local/share/locale\" -I. -I. -I.. -I. -I. -I../intl    -g -O2 -c `test -f 'output.c' || echo './'`output.c
output.c:26: error: static declaration of 'output' follows non-static declaration
indent.h:100: error: previous declaration of 'output' was here
output.c: In function 'open_output':
output.c:1149: warning: incompatible implicit declaration of built-in function 'exit'
make[3]: *** [output.o] Error 1
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

This same error happens on both Ubuntu Hardy and Mac OS X 10.5.



aaron