libnewt: fix recompile error

Fixed:
NOTE: make -j 32
make: *** No rule to make target `/path/to/sysroot/4.9.0/include/stddef.h', needed by `test.o'.  Stop.

This happens when upgrade gcc from 4.9.0 to 4.9.1, and the .depend isn't
regenerated when recompile, the content of the .depend are:

[snip]
test.o: /path/to/sysroot/4.9.0/include/stddef.h
[snip]

And Makefile includes the .depend file if it exists, so there would be
errors when /path/to/sysroot/4.9.0/include/stddef.h doesn't exist.

Remove .depend will fix the problem.

(From OE-Core rev: bf2f8abff4eb55cd960065eaba032c96068acf08)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/newt/libnewt_0.52.17.bb

@@ -46,4 +46,9 @@ do_configure_prepend() {
     sh autogen.sh
 }
 
+do_compile_prepend() {
+    # Make sure the recompile is OK
+    rm -f ${B}/.depend
+}
+
 FILES_whiptail = "${bindir}/whiptail"