Enable silent build by default

configure.ac

@@ -21,6 +21,9 @@ else
   AC_MSG_RESULT([RDRAND Hardware RNG Hash Seed disabled. Use --enable-rdrand to enable])
 fi
 
+# enable silent build by default
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes]]))
+
 # Checks for programs.
 
 # Checks for libraries.