ci(workflows): update android binder build configuration

Remove redundant environment variables and simplify binder module build rules
Use perl for more robust Makefile modifications

.github/workflows/build.yml

@@ -608,9 +608,6 @@ jobs:
         if: ${{ (inputs.android_version == 'android16' && inputs.kernel_version == '6.12' && inputs.os_patch_level == 'lts') && true}}
         working-directory: ${{ env.KERNEL_ROOT }}
         run: |
-          export RUST_LIB_SRC=$(pwd)/prebuilts/rust/linux-x86
-          export ALLOW_LOCAL_RUST_LIB=1
-          
           FILE=common/drivers/staging/android/ashmem.c
           if [[ -f "$FILE" ]] && ! grep -q 'is_ashmem_file' "$FILE"; then
           cat >>"$FILE" <<'EOF'
@@ -625,14 +622,12 @@ jobs:
           EXPORT_SYMBOL_GPL(ashmem_area_vmfile);
           EOF
           fi
-          
-          #if [[ "${{ inputs.os_patch_level }}" == "lts" ]]; then
-          #  sed -i 's/^obj-y += binder\//obj-m += binder\//' common/drivers/android/Makefile
-          #fi
-          
-          #sed -i -E 's/\$\(CONFIG_ANDROID_BINDER_IPC_RUST\)/m/' common/drivers/android/binder/Makefile
-          cat common/drivers/android/binder/Makefile
 
+          perl -i -pe 's/^obj-y\s*\+=\s*binder\/$/obj-\$(CONFIG_ANDROID_BINDER_IPC) += binder\//g' drivers/android/Makefile
+          cat common/drivers/android/Makefile
+          perl -i -pe 's/^\s*obj-\$(CONFIG_ANDROID_BINDER_IPC_RUST)\s*\+=[^ ]*rust_binder\.o$/obj-m += rust_binder.o/' drivers/android/binder/Makefile
+          cat common/drivers/android/binder/Makefile
+          
       - name: Change Kernel Name
         working-directory: ${{ env.KERNEL_ROOT }}
         run: |