[CMake] Macros in WebKitMacros.cmake should be prefixed with WEBKIT_ namespace

[CMake] Macros in WebKitMacros.cmake should be prefixed with WEBKIT_ namespace
https://bugs.webkit.org/show_bug.cgi?id=174547

Reviewed by Alex Christensen.

.:

* Source/cmake/WebKitMacros.cmake:

Source/JavaScriptCore:

* CMakeLists.txt:
* shell/CMakeLists.txt:

Source/ThirdParty:

* brotli/CMakeLists.txt:
* woff2/CMakeLists.txt:
* xdgmime/CMakeLists.txt:

Source/WebCore:

* CMakeLists.txt:
* WebCoreMacros.cmake:

Source/WebKit:

* CMakeLists.txt:

Source/WebKitLegacy:

* CMakeLists.txt:

Tools:

* DumpRenderTree/PlatformWin.cmake:
* DumpRenderTree/TestNetscapePlugIn/CMakeLists.txt:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@219578 268f45cc-cd09-0410-ab3c-d52691b4dbfc