autoconf: Reporting Messages

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1 10.3 Reporting Messages
1 =======================
1 
1 When macros statically diagnose abnormal situations, benign or fatal, it
1 is possible to make `autoconf' detect the problem, and refuse to create
1 `configure' in the case of an error.  The macros in this section are
1 considered obsolescent, and new code should use M4sugar macros for this
1 purpose, see ⇒Diagnostic Macros.
1 
1    On the other hand, it is possible to want to detect errors when
1 `configure' is run, which are dependent on the environment of the user
11 rather than the maintainer.  For dynamic diagnostics, see ⇒
 Printing Messages.
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1  -- Macro: AC_DIAGNOSE (CATEGORY, MESSAGE)
1      Report MESSAGE as a warning (or as an error if requested by the
1      user) if warnings of the CATEGORY are turned on.  This macro is
1      obsolescent; you are encouraged to use:
1           m4_warn([CATEGORY], [MESSAGE])
1      instead.  ⇒m4_warn, for more details, including valid
1      CATEGORY names.
1 
1  -- Macro: AC_WARNING (MESSAGE)
1      Report MESSAGE as a syntax warning.  This macro is obsolescent;
1      you are encouraged to use:
1           m4_warn([syntax], [MESSAGE])
1      instead.  ⇒m4_warn, for more details, as well as better
1      finer-grained categories of warnings (not all problems have to do
1      with syntax).
1 
1  -- Macro: AC_FATAL (MESSAGE)
1      Report a severe error MESSAGE, and have `autoconf' die.  This
1      macro is obsolescent; you are encouraged to use:
1           m4_fatal([MESSAGE])
1      instead.  ⇒m4_fatal, for more details.
1 
1    When the user runs `autoconf -W error', warnings from `m4_warn'
1 (including those issued through `AC_DIAGNOSE' and `AC_WARNING') are
1 reported as errors, see ⇒autoconf Invocation.
1