Fix merge-archives.sh Android build under Windows WSL2 (#575)

(cherry picked from commit cd69986)

tools/build/android/webrtc-native/build.gradle

@@ -78,8 +78,15 @@ dependencies {
 // Merge the libwebrtc.aar containing the Java interop classes for WebRTC
 // into the mrwebrtc.aar archive containing the native JNI library.
 task mergeLibwebrtcArchive(type: Exec) {
-   workingDir "$projectDir"
-   commandLine 'bash','./merge-archives.sh','-m',"$projectDir/build/outputs/aar/mrwebrtc.aar",'-o','./build/outputs/aar/merged/mrwebrtc.aar'
+    workingDir "$projectDir"   
+    println "Merge-archive.sh: Current working directory is $projectDir"
+
+    // For a Windows based path amount of backslashes is irrelevant, adding some more to escape
+    String WslRobustPath = "$projectDir".replaceAll("\\\\","\\\\\\\\")
+
+    commandLine 'bash','./merge-archives.sh','-m',
+                       "$WslRobustPath/build/outputs/aar/mrwebrtc.aar",'-o',
+                       './build/outputs/aar/merged/mrwebrtc.aar'
 }
 
 // Copy the final AAR archive to the Plugins folder of the Unity library.

tools/build/android/webrtc-native/merge-archives.sh

@@ -131,6 +131,20 @@ while getopts l:m:o:vh OPTION; do
     esac
 done
 
+# Update path for libwebrtc build under WSL2
+if grep -q microsoft /proc/version; then
+    echo "WSL-path-adaption: Detected WSL, adapting path now ..."
+    echo "Raw: ${MRWEBRTC_AAR}"
+    echo "Adapt to format: /mnt/\$driveletter\\windows_subdir\\..."
+    MRWEBRTC_AAR="$(sed -r 's/(^\w):/\/mnt\/\L\1/' <<< ${MRWEBRTC_AAR})"
+    echo "Intermediate path adaption result: ${MRWEBRTC_AAR}"
+    echo "Now adapt to format: /mnt/\$driveletter/windows_subdir/..."
+    MRWEBRTC_AAR="$(sed -r 's/\\/\//g' <<< ${MRWEBRTC_AAR})"
+    echo "Final path adaption result: ${MRWEBRTC_AAR}"
+else
+    echo "WSL-path-adaption: Detected native Linux, skipping path adaption!"
+fi
+
 # Ensure all arguments have reasonable values
 verify-arguments