When trying to build cerbero bootstrap on MacOSX, flex cannot generate its document without a proper texi2dvi utility.

libtool: install: /usr/bin/install -c flex /Users/joy/cerbero/build-tools/bin/flex
/Applications/Xcode.app/Contents/Developer/usr/bin/make  install-exec-hook
cd /Users/joy/cerbero/build-tools/bin && \
                ln -s -f flex flex++
 ./install-sh -c -d '/Users/joy/cerbero/build-tools/share/doc/flex'
 /usr/bin/install -c -m 644 AUTHORS COPYING NEWS ONEWS README TODO '/Users/joy/cerbero/build-tools/share/doc/flex'
 ./install-sh -c -d '/Users/joy/cerbero/build-tools/include'
 /usr/bin/install -c -m 644 FlexLexer.h '/Users/joy/cerbero/build-tools/include'
Making install in doc
restore=: && backupdir=".am$$" && \
        am__cwd=`pwd` && CDPATH="${ZSH_VERSION+.}:" && cd . && \
        rm -rf $backupdir && mkdir $backupdir && \
        if (/bin/sh /Users/joy/cerbero/sources/build-tools/flex-2.5.39/missing makeinfo --version) >/dev/null 2>&1; then \
          for f in flex.info flex.info-[0-9] flex.info-[0-9][0-9] flex.i[0-9] flex.i[0-9][0-9]; do \
            if test -f $f; then mv $f $backupdir; restore=mv; else :; fi; \
          done; \
        else :; fi && \
        cd "$am__cwd"; \
        if /bin/sh /Users/joy/cerbero/sources/build-tools/flex-2.5.39/missing makeinfo   -I . \
         -o flex.info flex.texi; \
        then \
          rc=0; \
          CDPATH="${ZSH_VERSION+.}:" && cd .; \
        else \
          rc=$?; \
          CDPATH="${ZSH_VERSION+.}:" && cd . && \
          $restore $backupdir/* `echo "./flex.info" | sed 's|[^/]*$||'`; \
        fi; \
        rm -rf $backupdir; exit $rc
TEXINPUTS=".:$TEXINPUTS" \
        MAKEINFO='/bin/sh /Users/joy/cerbero/sources/build-tools/flex-2.5.39/missing makeinfo   -I .' \
        texi2dvi --pdf --batch  --build-dir=flex.t2p -o flex.pdf  \
        flex.texi
/usr/bin/texi2dvi: Can't use option `--output' with more than one argument.
make[2]: *** [flex.pdf] Error 2
make[1]: *** [install-recursive] Error 1
make: *** [install] Error 2
Running command 'make install'

Recipe 'flex' failed at the build step 'install'
Select an action to proceed:
[0] Enter the shell
[1] Rebuild the recipe from scratch
[2] Rebuild starting from the failed step
[3] Skip recipe
[4] Abort

We can avoid this error by installing MacTex (https://tug.org/mactex/), but it's not good due to huge size of image if someone don't use tex on Mac.

Another solution which I proposed is just to make disable doc building.