Failure building Emacs on WSL

[Angelo Graziosi]

I build Emacs master on different system (Win64, GNU/Linux, OSX, WSL) monthly, 
but now it fails on WSL (Window Subsystem for Linux):

  [...]
  checking for brew... no
  configure: error: You do not seem to have makeinfo >= 4.13, and your
  source tree does not seem to have pre-built manuals in the 'info' directory.
  Either install a suitable version of makeinfo, or re-run configure
  with the '--without-makeinfo' option to build without the manuals.
  GNUmakefile:72: set di istruzioni per l'obiettivo "Makefile" non riuscito
  make: *** [Makefile] Errore 1

This didn't happened less than a month ago.. What changed? 

Thanks..