ADDITIONAL SYSTEM INFORMATION :
macOS 15.4.1 24E263 arm64
Apple clang version 17.0.0 (clang-1700.0.13.3)
OpenJDK 11.0.27

A DESCRIPTION OF THE PROBLEM :
When trying to build OpenJDK 11.0.27 on macOS 15.4.1 for MacPorts, I get an error saying 'expression is not an integral constant expression' for the expression '(-1)<<13' in src/jdk.pack/share/native/common-unpack/constants.h.

I've discussed this on the macports-dev mailinglist (https://lists.macports.org/pipermail/macports-dev/2025-April/046226.html), where it was suggested to replace this expression with '~0U<<13'. I don't know if this is the best fix, but this indeed makes OpenJDK 11.0.27 build on macOS 15.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to build OpenJDK 11.0.27 on macOS 15.4.1.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A successful build.
ACTUAL -
A failed build with an 'expression is not an integral constant expression' error message about '(-1)<<13' in src/jdk.pack/share/native/common-unpack/constants.h