Upgrades OpenGL header files to the latest Mesa project ones. Build+test looks fine.
------------- Commit messages: - 8262392: Update Mesa 3-D Headers to version 21.0.3 Changes: https://git.openjdk.java.net/jdk/pull/3854/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3854&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8262392 Stats: 144 lines in 6 files changed: 100 ins; 21 del; 23 mod Patch: https://git.openjdk.java.net/jdk/pull/3854.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/3854/head:pull/3854 PR: https://git.openjdk.java.net/jdk/pull/3854
