wpa-supplicant: fix for rebuild

Fixed when rebuild:
make: *** No rule to make target `/path/to/old//sysroots/qemux86-64/usr/lib/dbus-1.0/include/dbus/dbus-arch-deps.h', needed by `dbus/dbus_old.o'.  Stop.

The .d files save the path of the dependencies files which may not exist
when rebuild, we can remove them to make the rebuild work.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
sdk.py: fix write target sdk manifest failed based on ipk

bitbake meta-toolchain
ls tmp/deploy/sdk/poky-glibc-x86_64-meta-toolchain-i586-toolchain-1.7.manifest -al
...
|-rw-rw-r-- 1 root root 0 Oct 10 15:05 tmp/deploy/sdk/poky-glibc-x86_64-
meta-toolchain-i586-toolchain-1.7.manifest
...

The manifest is empty, the reason is target's ipk config path is
d.getVar('IPKGCONF_TARGET') rather than d.getVar('IPKGCONF_Target')

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
toolchains-scripts: Add support for target environment scripts

In a similar way to the previous script which adds support for native
environment scripts, this adds support for target environment scripts
too.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>