Fix output of --help regarding -W. Added new option --list-warnings.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5005 b7a2c559-68d2-44c3-8de9-860c34a00d81

doc/cc65.sgml

@@ -61,7 +61,7 @@ Short options:
   -Os                           Inline some known functions
   -T                            Include source as comment
   -V                            Print the compiler version number
-  -W                            Suppress warnings
+  -W warning[,...]              Suppress warnings
   -d                            Debug mode
   -g                            Add debug info to object file
   -h                            Help (this text)
@@ -92,6 +92,7 @@ Long options:
   --help                        Help (this text)
   --include-dir dir             Set an include directory search path
   --list-opt-steps              List all optimizer steps and exit
+  --list-warnings               List available warning types for -W
   --local-strings               Emit string literals immediately
   --memory-model model          Set the memory model
   --register-space b            Set space available for register variables
@@ -222,6 +223,13 @@ Here is a description of all the command line options:
   Print the short option summary shown above.
 
 
+  <label id="option-list-warnings">
+  <tag><tt>--list-warnings</tt></tag>
+
+  List the names of warning types available for use with <tt><ref
+  id="option-W" name="-W"></tt>.
+
+
   <label id="option-local-strings">
   <tag><tt>--local-strings</tt></tag>
 
@@ -491,6 +499,9 @@ Here is a description of all the command line options:
         Warn about unused variables.
   </descrip>
 
+  The full list of available warning names may be retrieved by using the
+  option <tt><ref id="option-list-warnings" name="--list-warnings"></tt>.
+
   You may also use <tt><ref id="pragma-warn" name="#pragma&nbsp;warn"></tt> to
   control this setting for smaller pieces of code from within your code.