provide stubs to ignore .ds, .rm and .tr,

which occur in the standard pod2man preamble;
from OpenBSD;
"sounds good" joerg@, "can be checked in" kristaps@

1 files changed, 18 insertions, 0 deletions

diff --git a/roff.7 b/roff.7
index c961db33..ed75a1e3 100644
--- a/roff.7
+++ b/roff.7
@@ -90,6 +90,12 @@ The syntax of this macro is the same as that of
 .Sx \&ig ,
 except that a leading argument must be specified.
 It is ignored, as are its children.
+.Ss \&ds
+Define a string.
+This macro is intended to have two arguments,
+the name of the string to define and its content.
+Currently, it is ignored including its arguments,
+and the number of arguments is not checked.
 .Ss \&de1
 The syntax of this macro is the same as that of
 .Sx \&ig ,
@@ -235,6 +241,18 @@ the subsequent invocation of
 .Sx \&if
 will first signify the end of comment, then be invoked as a macro.
 This behaviour really shouldn't be counted upon.
+.Ss \&rm
+Remove a request, macro or string.
+This macro is intended to have one argument,
+the name of the request, macro or string to be undefined.
+Currently, it is ignored including its arguments,
+and the number of arguments is not checked.
+.Ss \&tr
+Output character translation.
+This macro is intended to have one argument, 
+consisting of an even number of characters.
+Currently, it is ignored including its arguments,
+and the number of arguments is not checked.
 .Sh COMPATIBILITY
 This section documents compatibility between mandoc and other other
 troff implementations, at this time limited to GNU troff