my build = Module::Build->new(
     extra_compiler_flags => '... -mmacosx-version-min=11.0',
     extra_linker_flags   => '... -mmacosx-version-min=11.0',
 );

##</code><code>##

my $extra_cflags = $aug_cflags . ' ' . $libxml2_cflags . ' -Wall -Wformat -Werror=format-security';
my $extra_ldflags = $aug_libs . ' ' . $libxml2_cflags;
$extra_cflags =~ s/mmacosx-version-min=10\.13/mmacosx-version-min=11.0/g;
$extra_ldflags =~ s/mmacosx-version-min=10\.13/mmacosx-version-min=11.0/g;
print "Modified to $extra_cflags\n" ;
print "Modified to $extra_ldflags\n" ;


# insert the above before this:
print "Using $aug_libs and $aug_cflags to compile (Augeas version $aug_version)\n" ;
print "Using $libxml2_libs and $libxml2_cflags to compile (Augeas version $aug_version)\n" ;

##</code><code>##

my $build = Module::Build->new
  (
 ...
  extra_compiler_flags => $extra_cflags,
   extra_linker_flags   => $extra_ldflags,
 ...
);

##</code><code>##

perl -MConfig -e 'print $_.": ".$Config{$_}."\n" for keys %Config;'