AC_CONFIG_HEADERS([defines.h:defs.pre:defines.h.in:defs.post])

[Alexandre Duret-Lutz]

The documentation for AC_CONFIG_HEADERS(HEADER) reads

|     Usually the input file is named `HEADER.in'; however, you can
|     override the input file name by appending to HEADER a
|     colon-separated list of input files.  Examples:
|          
|          AC_CONFIG_HEADERS([config.h:config.hin])
|          AC_CONFIG_HEADERS([defines.h:defs.pre:defines.h.in:defs.post])

but if you run autoheader on a configure.ac containing only this 
second form, it creates a file named `defs.pre:defines.h.in:defs.post'!

I think I wouldn't expect autoheader to guess which of the three
input file it had to update, but I wouldn't expect it to create
such a grotesque file either.  Maybe it should issue diagnostic?
-- 
Alexandre Duret-Lutz