fix(ci,android): sed-based cdylib exclusion + armv7 NDK path fallback

- Temporarily strip cdylib from Cargo.toml before building non-arm64
  android targets (x86_64/i686/arm NDK libc.a has non-PIC objects)
- arm NDK path: try armv7a-linux-androideabi then arm-linux-androideabi

Author: Itsusinn

.github/workflows/build.yml

@@ -169,12 +169,14 @@ jobs:
         run: |
           # Export NDK bin to PATH for ar and other tools
           export PATH="${{ steps.setup-ndk.outputs.ndk-path }}/toolchains/llvm/prebuilt/linux-x86_64/bin:$PATH"
-          # Override crate-type to exclude cdylib: libcronet.a for
+          # Temporarily drop cdylib from Cargo.toml: libcronet.a for
           # x86_64/i686/arm-android was not compiled with -fPIC, so
-          # producing a cdylib (.so) fails with PIC relocation errors.
+          # cdylib (.so) linking fails with PIC relocation errors.
+          # We build only the rlib for these cross-compilation targets.
+          sed -i 's/crate-type = \["lib", "cdylib"\]/crate-type = ["lib"]/' Cargo.toml
           cargo build --target ${{ matrix.rust_target }} \
-            --features static-link \
-            --config 'lib.crate-type = ["lib"]'
+            --features static-link
+          git checkout -- Cargo.toml
 
   #############################################################################
   # macOS (Darwin) — static-link mode (.a downloaded)

build.rs

@@ -53,19 +53,20 @@ fn main() {
             if let Ok(ndk_home) = env::var("ANDROID_NDK_HOME") {
                 let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap_or_default();
                 let target_vendor = env::var("CARGO_CFG_TARGET_VENDOR").unwrap_or_default();
-                let ndk_target = match (target_arch.as_str(), target_vendor.as_str()) {
-                    ("aarch64", _) => "aarch64-linux-android",
-                    ("x86_64", _) => "x86_64-linux-android",
-                    ("arm", _) => "armv7a-linux-androideabi",
-                    ("x86", _) => "i686-linux-android",
-                    _ => "",
+                let ndk_candidates: &[&str] = match (target_arch.as_str(), target_vendor.as_str()) {
+                    ("aarch64", _) => &["aarch64-linux-android"],
+                    ("x86_64", _) => &["x86_64-linux-android"],
+                    ("arm", _) => &["armv7a-linux-androideabi", "arm-linux-androideabi"],
+                    ("x86", _) => &["i686-linux-android"],
+                    _ => &[],
                 };
-                if !ndk_target.is_empty() {
-                    let cxx_path = std::path::Path::new(&ndk_home)
-                        .join("toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib")
-                        .join(ndk_target);
+                let ndk_base = std::path::Path::new(&ndk_home)
+                    .join("toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib");
+                for candidate in ndk_candidates {
+                    let cxx_path = ndk_base.join(candidate);
                     if cxx_path.exists() {
                         println!("cargo:rustc-link-search=native={}", cxx_path.display());
+                        break;
                     }
                 }
             }