Makefile: unexport TOPDIR to fix gnu-efi >= 3.0.18 build issue
gnu-efi fails to build if TOPDIR is exported in the environment since the
move to version 3.0.18 in commit 9efeb7e914 ("package/gnu-efi: bump to
version 3.0.18").
The reason is the change in TOPDIR logic introduced by upstream commit
31913f8489 ("Make: make TOPDIR actually work and get rid of unused CDIR"):
https://github.com/ncroxon/gnu-efi/commit/31913f8489f8e6eb624b6447d2e5cf1f6367bebf
export TOPDIR=foo; make gnu-efi
...
/path/to/buildroot/output-gnuefi/host/bin/aarch64-linux-ld: cannot find
/path/to/buildroot/output-gnuefi/build/gnu-efi-4.0.0//apps/../aarch64/gnuefi/crt0-efi-aarch64.o:
No such file or director
make[2]: *** [Makefile:89: apps] Error 2
make[1]: *** [package/pkg-generic.mk:273: /path/to/buildroot/output-gnuefi/build/gnu-efi-4.0.0/.stamp_built] Error 2
make: *** [Makefile:23: _all] Error 2
As a workaround, unexport TOPDIR like we do for other sensitive environment
variables.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
Peter Korsgaard