fix(build): add x86 linker config for cargo cross-compilation

Without target-specific linker entries in .cargo/config.toml, cargo
falls back to the system cc which can't find -llog and -lunwind
from the Android sysroot.

Author: Enginex0

rust/.cargo/config.toml

@@ -3,3 +3,9 @@ linker = "aarch64-linux-android26-clang"
 
 [target.armv7-linux-androideabi]
 linker = "armv7a-linux-androideabi26-clang"
+
+[target.x86_64-linux-android]
+linker = "x86_64-linux-android26-clang"
+
+[target.i686-linux-android]
+linker = "i686-linux-android26-clang"