As follow-up to [JDK-8293499](https://bugs.openjdk.org/browse/JDK-8293499), JDK build can stick to lighter jmod compression levels to gain build performance.
# ----- Baseline $ time CONF=linux-x86_64-server-release make clean-images images real 0m10.762s user 1m5.157s sys 0m12.370s $ du -sk build/linux-x86_64-server-release/images/jdk/jmods/ 81480 build/linux-x86_64-server-release/images/jdk/jmods/ $ time CONF=linux-x86_64-server-release make clean-images images real 0m9.574s user 1m2.644s sys 0m12.143s $ du -sk build/linux-x86_64-server-release/images/jdk/jmods/ 85744 build/linux-x86_64-server-release/images/jdk/jmods/ This gets even more substantial if JVM is configured with `--with-native-debug-symbols=internal`, in which case `java.base` includes a much larger `libjvm.so`: # Baseline $ time CONF=linux-x86_64-server-release make clean-images images real 0m36.617s user 1m30.216s sys 0m11.692s $ du -sk build/linux-x86_64-server-release/images/jdk/jmods/ 295428 build/linux-x86_64-server-release/images/jdk/jmods/ # Patched $ time CONF=linux-x86_64-server-release make clean-images images real 0m22.183s user 1m13.841s sys 0m11.657s $ du -sk build/linux-x86_64-server-release/images/jdk/jmods/ 316856 build/linux-x86_64-server-release/images/jdk/jmods/ Users can use `--with-jmod-compress=zip-6` to get the original JMOD compression level back. Or, they can give up on compression altogether using `--with-jmod-compress=zip-0`, and then reap even more time benefits: $ time CONF=linux-x86_64-server-release make clean-images images real 0m6.411s user 0m56.145s sys 0m12.278s $ du -sk build/linux-x86_64-server-release/images/jdk/jmods/ 183752 build/linux-x86_64-server-release/images/jdk/jmods/ ------------- Commit messages: - Provide --with-jmod-compress configure option - Adopt new option format - Fix Changes: https://git.openjdk.org/jdk/pull/10214/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10214&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8293532 Stats: 36 lines in 4 files changed: 36 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/10214.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10214/head:pull/10214 PR: https://git.openjdk.org/jdk/pull/10214
