**Problem:** When cross-compiling, `PlatformProps.java` is regenerated during every incremental `make images` build, even when no source files have changed. This causes `java.base` and the JDK image to be rebuilt unnecessarily, increasing the build time.
The second build produced output such as: make CONF=linux-x86_64-server-release LOG=debug images > build.log 2>&1 rg -n 'Processing PlatformProps.java|Compiling up to .* files for java.base|Creating jdk image' build.log Processing PlatformProps.java [buildjdk] Processing PlatformProps.java Compiling up to 3396 files for java.base [buildjdk] Compiling up to 3396 files for java.base Creating jdk image **Fix:** Include the target OS and CPU in the name of `BUILD_PLATFORMPROPERTIES_JAVA`, so that the build JDK and target JDK use separate variable-dependency files and do not overwrite each other’s build state. **Testing:** Ran `make images` again without modifying any source files. The second build completed in about two seconds and no longer processed `PlatformProps.java`, rebuilt `java.base`, or recreated the JDK image. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - 8348737: PlatformProperties always triggers rebuild when cross compiling Changes: https://git.openjdk.org/jdk/pull/32593/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=32593&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8348737 Stats: 4 lines in 1 file changed: 1 ins; 0 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/32593.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/32593/head:pull/32593 PR: https://git.openjdk.org/jdk/pull/32593
