message: build: Check that Homebrew's berkeley-db4 package is actually installed
diff: @@ -639,13 +639,13 @@ case $host in
  dnl It's safe to add these paths even if the functionality is disabled by
  dnl the user (--without-wallet or --without-gui for example).
  openssl_prefix=`$BREW --prefix openssl 2>/dev/null`
  - bdb_prefix=$($BREW --prefix berkeley-db4 2>/dev/null)
  qt5_prefix=$($BREW --prefix qt5 2>/dev/null)
  if test x$openssl_prefix != x; then
  PKG_CONFIG_PATH="$openssl_prefix/lib/pkgconfig:$PKG_CONFIG_PATH"
  export PKG_CONFIG_PATH
  fi
  - if test x$bdb_prefix != x && test "x$BDB_CFLAGS" = "x" && test "x$BDB_LIBS" = "x" && test "$use_bdb" != "no"; then
  + if $BREW list --versions berkeley-db4 >/dev/null && test "x$BDB_CFLAGS" = "x" && test "x$BDB_LIBS" = "x" && test "$use_bdb" != "no"; then
  + bdb_prefix=$($BREW --prefix berkeley-db4 2>/dev/null)
  dnl This must precede the call to BITCOIN_FIND_BDB48 below.
  BDB_CFLAGS="-I$bdb_prefix/include"
  BDB_LIBS="-L$bdb_prefix/lib -ldb_cxx-4.8"
  