It accepted an optional argument to test for equality, but no way
to get the linker language of a particular target.
TARGET_PROPERTY provides this flexibility and STREQUAL provides
the necessary API for equality test.
Extend the CompileDefinitions test to cover accessing the
property of another target.
This command is similar to add_definitions, in that it affects
the compile options of all targets which follow it. The implementation
is similar to the implementation of the include_directories command,
in that it is based on populating a COMPILE_OPTIONS directory property
and using that to initialize the same property on targets.
Unlike the include_directories command however, the add_compile_options
command does not affect previously defined targets. That is, in
the following code, foo will not be compiled with -Wall, but bar
will be:
add_library(foo ...)
add_compile_options(-Wall)
add_library(bar ...)