RFR: 8254569: Remove hard dependency on Dispman in Monocle fb rendering [v6]

[Johan Vos]

> Allow the EGL functionality in monocle to leverage EGL-based systems. The low-level specific details about how the EGL calls should be constructed are left out, and a native interface (egl_ext.h) is created that can be mapped to any low-level system.

Johan Vos has updated the pull request incrementally with one additional commit since the last revision:

  change invocation of getEGLDisplayHandle into getEglDisplayHandle
  Conditionally add dlfcn

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Changes:
  - all: https://git.openjdk.java.net/jfx/pull/343/files
  - new: https://git.openjdk.java.net/jfx/pull/343/files/932fd001..dd6cf712

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=343&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=343&range=04-05

  Stats: 5 lines in 2 files changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/343.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/343/head:pull/343

PR: https://git.openjdk.java.net/jfx/pull/343