partial bitcoin#21205: actually stop configure if Boost isn't available

includes:
- c5da274

Author: kwvg

configure.ac

@@ -1411,11 +1411,8 @@ fi
 
 if test x$use_boost = xyes; then
 
-dnl Minimum required Boost version
-define(MINIMUM_REQUIRED_BOOST, 1.64.0)
-
-dnl Check for Boost libs
-AX_BOOST_BASE([MINIMUM_REQUIRED_BOOST])
+dnl Check for Boost headers
+AX_BOOST_BASE([1.64.0],[],[AC_MSG_ERROR([Boost is not available!])])
 if test x$want_boost = xno; then
     AC_MSG_ERROR([[only libdashconsensus can be built without boost]])
 fi