message: [Build] Improve clarity of bignum selection messages
diff: @@ -1031,27 +1031,30 @@ if test "x$use_ccache" = "xyes"; then
  fi
  dnl bignum value
  -if test x"$req_bignum" = x"auto"; then
  +set_bignum=$req_bignum
  +case $req_bignum in
  +auto)
  GMP_CHECK
  - if test x"$has_gmp" = x"yes"; then
  + if test x"$has_gmp" != x"yes"; then
  + AC_MSG_ERROR([gmp bignum automatically selected but libgmp is not available. Use depends,
  + install libgmp or select an other bignum implementation (ONLY gmp is fully SUPPORTED)])
  + else
  set_bignum=gmp
  fi
  -else
  - set_bignum=$req_bignum
  - case $set_bignum in
  + ;;
  gmp)
  GMP_CHECK
  if test x"$has_gmp" != x"yes"; then
  - AC_MSG_ERROR([gmp bignum explicitly requested but libgmp not available])
  + AC_MSG_ERROR([gmp bignum explicitly requested but libgmp is not available])
  fi
  ;;
  openssl)
  + AC_MSG_WARN([openssl bignum explicitly requested. This is DEPRECATED.])
  ;;
  *)
  AC_MSG_ERROR([invalid bignum implementation selection])
  ;;
  esac
  -fi
  dnl enable wallet
  AC_MSG_CHECKING([if wallet should be enabled])
  