FYI: -W error and back traces

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * doc/autoconf.texi (autoconf Invocation): Explain `-W error'
        gives back traces.

Index: doc/autoconf.texi
===================================================================
RCS file: /cvs/autoconf/doc/autoconf.texi,v
retrieving revision 1.382
diff -u -u -r1.382 autoconf.texi
--- doc/autoconf.texi 2000/11/10 16:56:22 1.382
+++ doc/autoconf.texi 2000/11/10 17:08:58
@@ -1012,8 +1012,41 @@
 
 @noindent
 If you want to disable @command{autoconf}'s defaults and @code{WARNING}
-but enable the warnings about obsolete constructs, use @samp{-W
+but enable the warnings about obsolete constructs, use @option{-W
 none,obsolete}.
+
address@hidden Back trace
address@hidden Macro invocation stack
address@hidden displays a back trace for errors, but not for
+warnings; if you want them, just pass @option{-W error}.  For instance
+on this @file{configure.in}:
+
address@hidden
+AC_DEFUN([INNER],
+[AC_TRY_RUN([true])])
+
+AC_DEFUN([OUTTER],
+[INNER])
+
+AC_INIT
+OUTTER
address@hidden example
+
address@hidden
+you get:
+
address@hidden
+/tmp % ace -Wcross
+configure.in:8: warning: AC_TRY_RUN called without default to allow \
+cross compiling
+/tmp % ace -Wcross,error
+configure.in:8: error: AC_TRY_RUN called without default to allow \
+cross compiling
+acgeneral.m4:3044: AC_TRY_RUN is expanded from...
+configure.in:2: INNER is expanded from...
+configure.in:5: OUTTER is expanded from...
+configure.in:8: the top level
address@hidden example
 
 @item address@hidden:@var{format}]
 @itemx -t @var{macro}[:@var{format}]