All compilers on APPLE use ld64

[RJVB]

The current compiler settings module limits Mac users to building with the system compiler:

lxqt-build-tools/cmake/modules/LXQtCompilerSettings.cmake

Line 159 in 5aa946a

if (${CMAKE_CXX_COMPILER_ID} STREQUAL AppleClang)

Using e.g. a newer clang from MacPorts or HB will cause the link step to fail.

Assuming that lxqt code will only be built on desktop systems the correct test is simply

if (APPLE)