autoconf not found on Ubuntu even when installed

During compilation on Ubuntu:

git -C /home/bbs/sbbs-git/repo remote set-url origin https://gitlab.synchro.net/main/sbbs.git
echo MAKEFLAGS= os=linux RELEASE=1 | tr ' ' '\n' > /home/bbs/sbbs-git/repo/src/build/localdefs.mk
make -C /home/bbs/sbbs-git/repo/src/sbbs3 MAKEFLAGS= os=linux RELEASE=1 setcap
make[1]: Entering directory '/home/bbs/sbbs-git/repo/src/sbbs3'
diff: git_hash.h: No such file or directory
diff: git_branch.h: No such file or directory
make -C /home/bbs/sbbs-git/repo/src/sbbs3/../../3rdp/build jslib
make[2]: Entering directory '/home/bbs/sbbs-git/repo/3rdp/build'
Creating ../build/../../src/../3rdp/gcc.linux.x64.release/mozjs/lib/libmozjs185-1.0.a ...
patching file js/src/jsnativestack.cpp
patching file js-1.8.5/js/src/configure
patching file js-1.8.5/js/src/configure.in
patching file js-1.8.5/js/src/imacro_asm.py
patching file ./js-1.8.5/js/src/methodjit/MethodJIT.cpp
patching file js-1.8.5/js/src/jsutil.h
patching file js-1.8.5/js/src/configure.in
patching file js-1.8.5/js/src/build/autoconf/config.guess
patching file js-1.8.5/js/src/Makefile.in
/bin/sh: 1: autoconf-2.13: not found

This is because autoconf 2.13 is installed as autoconf2.13

bbs@test:~/sbbs-git$ which autoconf2.13 /usr/bin/autoconf2.13

The makefile should probably check for various versions, if it's actually important.