Fix aarch64 Linux builds with QEMU, nightly Rust, and cross configuration

- Add Docker Buildx and QEMU setup for ARM64 emulation
- Switch to nightly Rust toolchain (required for Rust 1.88.0)
- Configure Cross.toml with ARM64 package installation and library paths
- Set CROSS_NO_WARNINGS=0 to ignore post-install script warnings
- Add CMake environment variables for Kafka builds to find ARM64 libs

Author: nikhilsinhaparseable

.github/workflows/build.yaml

@@ -62,6 +62,8 @@ jobs:
 
       - name: Build with cross
         if: matrix.use_cross
+        env:
+          CROSS_NO_WARNINGS: "0"
         run: cross build --target ${{ matrix.target }} --release
 
       - name: Build native
@@ -201,13 +203,15 @@ jobs:
         env:
           LIBRDKAFKA_SSL_VENDORED: "1"
           PKG_CONFIG_ALLOW_CROSS: "1"
+          CROSS_NO_WARNINGS: "0"
+          RUST_BACKTRACE: "1"
           ZLIB_INCLUDE_DIR: "/usr/include/aarch64-linux-gnu"
           ZLIB_LIBRARY: "/usr/lib/aarch64-linux-gnu/libz.so"
-          OPENSSL_DIR: "/usr"
-          OPENSSL_LIB_DIR: "/usr/lib/aarch64-linux-gnu"
+          OPENSSL_ROOT_DIR: "/usr"
           OPENSSL_INCLUDE_DIR: "/usr/include/aarch64-linux-gnu"
-          CROSS_NO_WARNINGS: "0"
-          RUST_BACKTRACE: "1"
+          OPENSSL_CRYPTO_LIBRARY: "/usr/lib/aarch64-linux-gnu/libcrypto.so"
+          OPENSSL_SSL_LIBRARY: "/usr/lib/aarch64-linux-gnu/libssl.so"
+          PKG_CONFIG_PATH: "/usr/lib/aarch64-linux-gnu/pkgconfig"
         run: cross build --target ${{ matrix.target }} --features kafka --release --verbose
 
       - name: Build with Kafka (native)

Cross.toml

@@ -10,13 +10,15 @@ pre-build = [
 passthrough = [
     "LIBRDKAFKA_SSL_VENDORED",
     "PKG_CONFIG_ALLOW_CROSS",
+    "CROSS_NO_WARNINGS",
+    "RUST_BACKTRACE",
     "ZLIB_INCLUDE_DIR",
     "ZLIB_LIBRARY",
-    "OPENSSL_DIR",
-    "OPENSSL_LIB_DIR",
+    "OPENSSL_ROOT_DIR",
     "OPENSSL_INCLUDE_DIR",
-    "CROSS_NO_WARNINGS",
-    "RUST_BACKTRACE",
+    "OPENSSL_CRYPTO_LIBRARY",
+    "OPENSSL_SSL_LIBRARY",
+    "PKG_CONFIG_PATH",
 ]
 volumes = [
     "/usr/lib/aarch64-linux-gnu:/usr/lib/aarch64-linux-gnu:ro",