Problem with autoconf autodepend

[Ken Brown]

The build of emacs from cvs source recently started failing because the 
build system added autodepend support.  The associated configure test 
succeeds, but the feature itself doesn't work reliably.  The simple 
workaround is to configure with --disable-autodepend, but I thought I 
should report this in case it indicates a cygwin problem and/or an 
autoconf problem.  Of course, I'd also like to know if it's an emacs 
problem so I can report it to them.

Here's the relevant excerpt from configure.in:

    if test $HAVE_GNU_MAKE = yes; then
       AC_MSG_CHECKING([whether gcc understands -MMD -MF])
       SAVE_CFLAGS="$CFLAGS"
       CFLAGS="$CFLAGS -MMD -MF deps.d"
       AC_TRY_COMPILE([], [], , ac_enable_autodepend=no)
       CFLAGS="$SAVE_CFLAGS"
       test -f deps.d || ac_enable_autodepend=no
       rm -rf deps.d
       AC_MSG_RESULT([$ac_enable_autodepend])
    fi
    if test $ac_enable_autodepend = yes; then
       AC_DEFINE(AUTO_DEPEND, 1, [Generate dependencies with gcc.])
    fi

And here's the build failure:

gcc -c -Demacs -DHAVE_CONFIG_H  -I. -I/tmp/emacs/src 
-I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/atk-1.0 
-I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 
-I/usr/lib/glib-2.0/include -I/usr/include/pixman-1 
-I/usr/include/freetype2 -I/usr/include/libpng12 
-I/usr/include/freetype2     -g -O2 -Wdeclaration-after-statement 
-Wno-pointer-sign   -MMD -MF deps/ecrt0.d /tmp/emacs/src/ecrt0.c
/tmp/emacs/src/ecrt0.c:106: fatal error: opening dependency file 
deps/ecrt0.d: No such file or directory

Ken

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