[m-rev.] diff: add synonyms for some command line options

[Julien Fischer]

Add synonyms for some command line options.

compiler/options.m:
doc/user_guide.texi:
 	'vars' is used as a abbreviation for 'variables' in all compiler
 	command line options except two: --no-warn-singleton-variables and
 	--no-warn-undefined-options-variables.  Add synonyms for these options
 	that use 'vars'.

Julien.

diff --git a/compiler/options.m b/compiler/options.m
index ee2bd2c..5ca97a5 100644
--- a/compiler/options.m
+++ b/compiler/options.m
@@ -1981,6 +1981,7 @@ long_option("halt-at-warn",             halt_at_warn).
  long_option("halt-at-syntax-errors",    halt_at_syntax_errors).
  long_option("halt-at-auto-parallel-failure", halt_at_auto_parallel_failure).
  long_option("warn-singleton-variables", warn_singleton_vars).
+long_option("warn-singleton-vars",      warn_singleton_vars).
  long_option("warn-overlapping-scopes",  warn_overlapping_scopes).
  long_option("warn-det-decls-too-lax",   warn_det_decls_too_lax).
  long_option("warn-inferred-erroneous",  warn_inferred_erroneous).
@@ -2003,6 +2004,8 @@ long_option("warn-wrong-module-name",   warn_wrong_module_name).
  long_option("warn-smart-recompilation", warn_smart_recompilation).
  long_option("warn-undefined-options-variables",
                      warn_undefined_options_variables).
+long_option("warn-undefined-options-vars",
+                    warn_undefined_options_variables).
  long_option("warn-non-tail-recursion",  warn_non_tail_recursion).
  long_option("warn-target-code",         warn_target_code).
  long_option("warn-up-to-date",          warn_up_to_date).
@@ -3516,7 +3519,7 @@ options_help_warning -->
          "--inhibit-accumulator-warnings",
          "\tDon't warn about argument order rearrangement caused",
          "\tby --introduce-accumulators.",
-        "--no-warn-singleton-variables",
+        "--no-warn-singleton-vars, --no-warn-singleton-variables",
          "\tDon't warn about variables which only occur once.",
          "--no-warn-overlapping-scopes",
          "\tDon't warn about variables which occur in overlapping scopes.",
@@ -3579,6 +3582,7 @@ options_help_warning -->
          "\tdeclaration does not match the module's file name.",
          "--no-warn-smart-recompilation",
          "\tDisable warnings from the smart recompilation system.",
+        "--no-warn-undefined-options-vars",
          "--no-warn-undefined-options-variables",
          "\tDo not warn about references to undefined variables in",
          "\toptions files with `--make'.",
diff --git a/doc/user_guide.texi b/doc/user_guide.texi
index d957e0d..be8d0ce 100644
--- a/doc/user_guide.texi
+++ b/doc/user_guide.texi
@@ -6432,8 +6432,11 @@ Don't warn about argument order rearrangement caused by
  @samp{--introduce-accumulators}.

  @sp 1
- at item --no-warn-singleton-variables
+ at item --no-warn-singleton-vars
+ at itemx --no-warn-singleton-variables
+ at findex --no-warn-singleton-vars
  @findex --no-warn-singleton-variables
+ at findex --warn-singleton-vars
  @findex --warn-singleton-variables
  Don't warn about variables which only occur once.

@@ -6558,7 +6561,9 @@ does not match the module's file name.
  Disable warnings from the smart recompilation system.

  @sp 1
- at item --no-warn-undefined-options-variables
+ at item --no-warn-undefined-options-vars
+ at itemx --no-warn-undefined-options-variables
+ at findex --no-warn-undefined-options-vars
  @findex --no-warn-undefined-options-variables
  @findex --make
  Do not warn about references to undefined variables in