Building server with Temurin fails

- [x] I have read the [FAQ](https://github.com/Genymobile/scrcpy/blob/master/FAQ.md).
- [x] I have searched in existing [issues](https://github.com/Genymobile/scrcpy/issues).

**Environment**
- OS: macOS 10.15.7 with Homebrew
- scrcpy version: 2.4 and dev
- installation method: manual build

```
java --version
openjdk 21.0.3 2024-04-16 LTS
OpenJDK Runtime Environment Temurin-21.0.3+9 (build 21.0.3+9-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.3+9 (build 21.0.3+9-LTS, mixed mode)
```

**Trying to build the server with Temurin fails.**
Not clear if it should be possible (or if it reveals a `scrcpy` bug or a Temurin bug).

Might not be an issue, but reporting it might help someone find this build failure cause faster. ;)

**Idea**
Could be helpful to add `java --version` to `server/build_without_gradle.sh`.

```
./server/build_without_gradle.sh
Platform: android-34
Build-tools: 34.0.0
Build dir: /Users/Shared/src/scm/android/scrcpy/build_manual
Generating java from aidl...
Compiling java sources...
warning: [options] source value 8 is obsolete and will be removed in a future release
warning: [options] target value 8 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
3 warnings
Dexing...
Error in com/genymobile/scrcpy/AudioCodec.class:
java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null
Compilation failed with an internal error.
Exception in thread "main" java.lang.RuntimeException: com.android.tools.r8.CompilationFailedException: Compilation failed to complete, origin: com/genymobile/scrcpy/AudioCodec.class
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:126)
at com.android.tools.r8.D8.main(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:5)
Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete, origin: com/genymobile/scrcpy/AudioCodec.class
at Version.fakeStackEntry(Version_8.2.2-dev.java:0)
at com.android.tools.r8.M.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:5)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:81)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:32)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:31)
at com.android.tools.r8.utils.R0.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:2)
at com.android.tools.r8.D8.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:26)
at com.android.tools.r8.D8.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:13)
at com.android.tools.r8.D8.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:24)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:113)
... 1 more
Caused by: java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null
at com.android.tools.r8.graph.u2.(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:5)
at com.android.tools.r8.graph.p1.c(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:3)
at com.android.tools.r8.graph.Q3.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:10)
at com.android.tools.r8.internal.Ga.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:873)
at com.android.tools.r8.graph.T3.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:44)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:129)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:130)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:128)
at com.android.tools.r8.graph.T3.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:2)
at com.android.tools.r8.dex.a.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:27)
at java.base/java.util.concurrent.ForkJoinTask$AdaptedCallable.exec(ForkJoinTask.java:1456)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188)
Suppressed: java.lang.RuntimeException: java.util.concurrent.ExecutionException: com.android.tools.r8.utils.T0: java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null
at com.android.tools.r8.dex.c.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:60)
at com.android.tools.r8.dex.c.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:9)
at com.android.tools.r8.dex.c.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:8)
at com.android.tools.r8.D8.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:29)
at com.android.tools.r8.D8.d(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:17)
at com.android.tools.r8.D8.c(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:1)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:28)
at com.android.tools.r8.utils.R0.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:2)
at com.android.tools.r8.D8.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:26)
at com.android.tools.r8.D8.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:13)
at com.android.tools.r8.D8.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:24)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:113)
at com.android.tools.r8.D8.main(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:5)
Caused by: java.util.concurrent.ExecutionException: com.android.tools.r8.utils.T0: java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null
at java.base/java.util.concurrent.ForkJoinTask.reportExecutionException(ForkJoinTask.java:581)
at java.base/java.util.concurrent.ForkJoinTask.get(ForkJoinTask.java:993)
at com.android.tools.r8.utils.d3.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:64)
at com.android.tools.r8.dex.c.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:41)
... 12 more
Caused by: com.android.tools.r8.utils.T0: java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:149)
at com.android.tools.r8.utils.R0.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:128)
at com.android.tools.r8.graph.T3.b(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:2)
at com.android.tools.r8.dex.a.a(R8_8.2.2-dev_53a55043254cc5be8ef500331bba25d1b4ca4bc2cd66c555d4358bf672a1f10a:27)
at java.base/java.util.concurrent.ForkJoinTask$AdaptedCallable.exec(ForkJoinTask.java:1456)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188)
Caused by: [CIRCULAR REFERENCE: java.lang.NullPointerException: Cannot invoke "String.length()" because "" is null]
```

**Solution**
Switching back to the openjdk installed by `Homebrew`.
```
java --version
openjdk 19.0.1 2022-10-18
OpenJDK Runtime Environment Homebrew (build 19.0.1)
OpenJDK 64-Bit Server VM Homebrew (build 19.0.1, mixed mode, sharing)

./server/build_without_gradle.sh
Platform: android-34
Build-tools: 34.0.0
Build dir: /Users/Shared/src/scm/android/scrcpy/build_manual
Generating java from aidl...
Compiling java sources...
Dexing...
Server generated in /Users/Shared/src/scm/android/scrcpy/build_manual/scrcpy-server
```

Start with server/build_without_gradle.sh and reproduce the reported failure using Temurin 21, then compare it with the successful Homebrew OpenJDK 19 build. Inspect the Java compilation and D8/R8 steps around the AudioCodec.class error. Done means identifying whether the failure is caused by Temurin, the build tools, or scrcpy, and documenting or fixing the supported build behavior.

Written by the indexing model from the issue text.