Some macros provided by autoconf do automatically issue screen
output when called, for example AC_CHECK_LIB. This may be
undesirable at times, for example when these routines are called
within a more complex macro consisting of several tests in a row.
Hence this macro provides a mechanism to switch screen output by
autoconf generally off. All screen i/o within configure scripts
takes place on file descriptor "6", which is in fact a copy of
the standard output. By setting this file descriptor to
"/dev/null" or to standard output again, silent mode can be
enabled or disabled.
PETI_SILENT_MODE(on) dnl be silent
PETI_SILENT_MODE(off) dnl talk to me again
This macro was proposed and inspired by Paolo Bonzini <firstname.lastname@example.org>.