Fix warning.
Merge topic 'minor-fixes' into next

9f04495 Fix warning.
Deduplicate the isGeneratorExpression method.

This API seems like the most appropriate.
De-duplicate validation of genex target names.
Test printing origin of include dirs from tll().
The COMPATIBLE_INTERFACE does not affect the target it is set on.

Test and document this.
Ensure type specific compatible interface properties do not intersect.

Before, the boolean version would always win, and the string one would
be ignored.
Fix generation of COMPILE_DEFINITIONS in DependInfo.cmake.

As INTERFACE_COMPILE_DEFINITIONS are now possible, we can have
situations like this:

 add_library(foo ...)
 add_library(bar ...)
 target_link_libraries(foo bar)

 target_compile_definitions(bar INTERFACE SOME_DEF)

The INTERFACE_COMPILE_DEFINITIONS of bar determine how foo should be
compiled, and if they change, foo should be rebuilt.

Additionally, as of commit d1446ca7 (Append the COMPILE_DEFINITIONS
from the Makefile to all targets., 2012-09-17), we don't need to
read definitions from the makefile if we read them from the target,
so also de-duplicate the cached info.

The DependInfo for INTERFACE_INCLUDE_DIRECTORIES is already handled
correctly.
Merge topic 'minor-fixes' into next

2da342e Fix generation of COMPILE_DEFINITIONS in DependInfo.cmake.
65d1cab Ensure type specific compatible interface properties do not intersect.
114e053 The COMPATIBLE_INTERFACE does not affect the target it is set on.
e0e9642 Test printing origin of include dirs from tll().
52c9f98 De-duplicate validation of genex target names.
5d590aa Deduplicate the isGeneratorExpression method.