Correct a few manpage formatting glitches.

diff -ur libXt-1.0.5.orig/util/makestrs.man libXt-1.0.5/util/makestrs.man
--- libXt-1.0.5.orig/util/makestrs.man	2007-01-03 02:47:31.000000000 +0100
+++ libXt-1.0.5/util/makestrs.man	2008-10-07 12:11:23.000000000 +0200
@@ -40,16 +40,16 @@
 is not specified
 .I makestrs
 will read from
-.I stdin.
+.IR stdin .
 The C source file is always written to
-.I stdout.
+.IR stdout .
 .I makestrs
 creates one or more C header files as specified in the source file.
 The following options may be specified:
-.I -sparcabi,
-.I -intelabi,
-.I -functionabi,
-.I -arrayperabi,
+.IR -sparcabi ,
+.IR -intelabi ,
+.IR -functionabi ,
+.IR -arrayperabi ,
 and
 .I -defaultabi.
 .LP