AC_INIT

AC_CHECK_PROGS([MAKE], [make], [no])
AS_IF([test "$MAKE" == "no"], 
      [AC_MSG_NOTICE([without GNU Make, you have to inspect 'Makefile' and deduce build targets yourself.])])

AC_CHECK_PROGS([GIT], [git], [no])
AS_IF([test "$GIT" == "no"], 
      [AC_MSG_ERROR([install Git, before continuing.])])

AC_CHECK_PROGS([PYTHON3], [python3], [no])
AS_IF([test "$PYTHON3" == "no"],
      [AC_MSG_ERROR([install Python 3, before continuing.])])

# required in Makefile to ensure proper path resolution during preprocessing
# realpath is not available on macOS
AC_CHECK_PROGS([REALPATH], [realpath], [no])
AS_IF([test "$REALPATH" == "no"], 
      [AC_MSG_ERROR([set a persistent alias for 'realpath', before continuing, e.g.

alias='python3 -c "import pathlib,sys;print(pathlib.Path(sys.argv[[1]]).resolve())"'"
])])

AC_MSG_NOTICE([initializing python3 venv...])
make .venv

AC_OUTPUT