tlbuild: --enable-silent-rules

 
 7.1.10 '--enable-silent-rules'
 ------------------------------
 
 Enable the use of less verbose build rules.  When using GNU 'make' (or
 any 'make' implementation supporting nested variable expansions), you
 can specify 'V=1' on the 'make' command line to get more verbosity, or
 'V=0' to get less, regardless of this option.