fix(libutil/tarfile): add option to libarchive so it behaves correctl…

…y with AppleDouble files

AppleDouble files were extracted differently on macOS machines than on other
UNIX's.
Setting `archive_read_set_format_option(this->archive, NULL ,"mac-ext",NULL)`
fixes this problem, since it just ignores the AppleDouble filel and treats it as
a normal one.
This was a problem since it caused source archives to be different between macOS
and Linux.

Ref: NixOS#9290

src/libutil/tarfile.cc

@@ -53,6 +53,7 @@ TarArchive::TarArchive(Source & source, bool raw) : buffer(65536)
         archive_read_support_format_raw(archive);
         archive_read_support_format_empty(archive);
     }
+    archive_read_set_option(archive, NULL, "mac-ext", NULL);
     check(archive_read_open(archive, (void *)this, callback_open, callback_read, callback_close), "Failed to open archive (%s)");
 }
 
@@ -63,6 +64,7 @@ TarArchive::TarArchive(const Path & path)
 
     archive_read_support_filter_all(archive);
     archive_read_support_format_all(archive);
+    archive_read_set_option(archive, NULL, "mac-ext", NULL);
     check(archive_read_open_filename(archive, path.c_str(), 16384), "failed to open archive: %s");
 }