document issue with BSD make and obj/

[Alexandre Duret-Lutz]

Ok to commit?

2002-07-22  Alexandre Duret-Lutz  <address@hidden>

        * doc/autoconf.texi (Limitations of Make): Mention the special
        handling of the obj/ directory by BSD make.

Index: doc/autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.649
diff -u -r1.649 autoconf.texi
--- doc/autoconf.texi   20 Jul 2002 00:14:59 -0000      1.649
+++ doc/autoconf.texi   22 Jul 2002 20:00:07 -0000
@@ -10395,6 +10395,31 @@
         # foo
 @end example
 
address@hidden The @file{obj/} subdirectory.
address@hidden @file{obj/}, subdirectory
address@hidden BSD make and @file{obj/}
+
+Never name one of your subdirectories @file{obj/} if you don't like
+surprises.
+
+If an @file{obj/} directory exists, BSD make will enter it
+before reading @file{Makefile}.  Hence the @file{Makefile} in the
+current directory will not be read.
+
address@hidden
+% @kbd{cat Makefile}
+all:
+        echo Hello
+% @kbd{cat obj/Makefile}
+all:
+        echo World
+% @kbd{make}      # GNU make
+echo Hello
+Hello
+% @kbd{pmake}     # BSD make
+echo World
+World
address@hidden example
 
 @item @code{VPATH}
 @cindex @code{VPATH}
-- 
Alexandre Duret-Lutz