Add sections to the cmake-buildsystem(7) manual and cross-reference
them with relevant variables and target properties. This avoids
duplicating the information and allows it to be more detailed.
Re-organize the content added to the cmake-packages(7) manual by
* commit v3.0.0-rc1~184^2 (Help: Document export(EXPORT) in the
cmake-packages manual, 2013-12-23),
* commit v3.0.0-rc1~154^2~1 (Help: Add notes about relocatability
of config-file packages, 2014-01-07), and
* commit v3.2.0-rc1~345^2 (Help: Warn that paths should not be used
in INTERFACE_ build properties, 2014-11-22).
These commits broke the natural flow of the original manual and made
wording after the new content make less sense. Move the content into
new subsections to restore the flow of the original manual and to
make explicitly the purpose of the new content.
Shorten the relocatable usage requirement "warnings". Refer to the
new cmake-packages(7) manual subsection to reduce duplication. Also
clarify the distinction between paths to library dependencies and
paths to their header files.
Fix cmTarget::GetSourceFiles to set EvaluateForBuildsystem on the
$<TARGET_PROPERTY:...,INTERFACE_SOURCES> generator expression so that
the $<TARGET_OBJECTS> generator expression is allowed within an
INTERFACE_SOURCES value.
Extend the InterfaceLibrary test to cover this case. Extend the
RunCMake.TargetObjects test to cover failure of $<TARGET_OBJECTS>
when used through $<TARGET_PROPERTY:...,INTERFACE_SOURCES> in a
non-buildsystem context.
The add_library(INTERFACE) and Interface Libraries documentation
list all the INTERFACE_* properties and target_* commands that
can be used to define the interface. Add INTERFACE_SOURCES
and target_sources() to these lists for completeness.
This is the convention suggested in the Sphinx documentation and is
already used in several other places in the CMake documentation.
Update a few places where we were using other characters.
Explain how to use $<BUILD_INTERFACE> and $<INSTALL_INTERFACE> directly
in the documentation of the target_include_directories command and
INTERFACE_INCLUDE_DIRECTORIES target property. Otherwise readers need
to notice the link to the cmake-buildsystem(7) manual and find the
example in that to understand the need for these expressions.
Also fix the explanation in cmake-buildsystem(7) to not claim that
relative paths may be used inside a BUILD_INTERFACE expression.
People will be tempted to put things there for convenience, thereby
causing conflicts similar to
http://thread.gmane.org/gmane.comp.compilers.clang.devel/35162/focus=35169
where it is conceivable that the LLVM developers could put a flag on
a target for convenience, which would cause conflicts for some downstreams.
Describe how to define a buildsystem of binary targets, how to
express dependencies between them, how to add build specifications,
how to specify usage requirements, transitive and compatible
propagation and the various pseudo targets.
