missing file paper.h 4.15 and 4.15.1

libtool: compile:  gcc -DHAVE_CONFIG_H -I.
-I../../../work/a2ps-4.15.1/liba2ps -I.. -I.. -I../../../work/
a2ps-4.15.1/liba2ps -I../../../work/a2ps-4.15.1/lib -I../lib
-DLOCALEDIR=\"/home/carl/gsrc/share/locale\"
-DSYSCONFFILE=\"/home/carl/gsrc/etc/a2ps.cfg\" -DHAVE_CONFIG_H -g -O2
-MT gc-stubs.lo -MD -MP -MF .deps/
gc-stubs.Tpo -c ../../../work/a2ps-4.15.1/liba2ps/gc-stubs.c -o gc-stubs.o
../../../work/a2ps-4.15.1/liba2ps/jobs.c:25:10: fatal error: paper.h:
No such file or directory
  25 | #include <paper.h>
     |          ^~~~~~~~~
compilation terminated.

where does "paper.h" come from?