automake: always use correct path for aclocal.real
Before this commit, it was assumed that aclocal.real is in the PATH. While
this was fine for the normal build workflow, this led to some issues if
make TOPDIR="$(pwd)" -C "$pkgdir" compile
was called manually. The command failed with:
/home/.../openwrt/staging_dir/host/bin/aclocal: line 2: aclocal.real: command not found
autoreconf: /home/.../openwrt/staging_dir/host/bin/aclocal failed with exit status: 127
After the commit, the package is built sucessfully.
Signed-off-by: Leonardo Mörlein <me@irrelefant.net>