On Solaris 11.4, the "gmake check" command in automake-1.16j appears to hang.
Using 'truss', I found that it invokes
  /usr/bin/lex --version
and that command reads from standard input:

  $ /usr/bin/lex --version
  lex: Software Generation Utilities (SGU) Solaris-ELF (4.0)
  _

The attached proposed patch fixes it.