Fix spacing markup and other sundries.
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index a6617e3..6a44029 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -421,7 +421,7 @@
Return system configuration information relevant to an open file.
\var{name} specifies the configuration value to retrieve; it may be a
string which is the name of a defined system value; these names are
-specified in a number of standards (\POSIX.1, \UNIX 95, \UNIX 98, and
+specified in a number of standards (\POSIX.1, \UNIX{} 95, \UNIX{} 98, and
others). Some platforms define additional names as well. The names
known to the host operating system are given in the
\code{pathconf_names} dictionary. For configuration variables not
@@ -793,7 +793,7 @@
Return system configuration information relevant to a named file.
\var{name} specifies the configuration value to retrieve; it may be a
string which is the name of a defined system value; these names are
-specified in a number of standards (\POSIX.1, \UNIX 95, \UNIX 98, and
+specified in a number of standards (\POSIX.1, \UNIX{} 95, \UNIX{} 98, and
others). Some platforms define additional names as well. The names
known to the host operating system are given in the
\code{pathconf_names} dictionary. For configuration variables not
@@ -1080,7 +1080,7 @@
of its subdirectories (directories are generated bottom up).
When \var{topdown} is true, the caller can modify the \var{dirnames} list
-in-place (e.g., via \keyword{del} or slice assignment), and
+in-place (perhaps unsing \keyword{del} or slice assignment), and
\function{walk()} will only recurse into the subdirectories whose names
remain in \var{dirnames}; this can be used to prune the search,
impose a specific order of visiting, or even to inform \function{walk()}
@@ -1667,7 +1667,7 @@
Return string-valued system configuration values.
\var{name} specifies the configuration value to retrieve; it may be a
string which is the name of a defined system value; these names are
-specified in a number of standards (\POSIX, \UNIX 95, \UNIX 98, and
+specified in a number of standards (\POSIX, \UNIX{} 95, \UNIX{} 98, and
others). Some platforms define additional names as well. The names
known to the host operating system are given in the
\code{confstr_names} dictionary. For configuration variables not