Each call to AddDefinition has overhead for variable watches and such.
Avoid extra calls when not needed.
This decreases the configure time for ParaView by 10 seconds on my
machine. Without the change about 1,000,000 set-to-empty calls were
being made. After the change it drops to about 100,000.
The SHA512_Update implementation accesses input data via 64-bit
integers. This requires alignment of the input buffer on some
architectures. Align our stack-allocated buffer for file content to
satisfy this requirement.
Describe explicitly the scope in which enable_language must be
invoked to handle all direct and indirect uses of a language.
While at it, re-word documentation of the OPTIONAL keyword to
avoid confusion over its partial implementation.
If the expression $<TARGET_PROPERTY:prop> appears in the content
of a target property, the target that prop is read from is
the 'head target' of the expression. In contexts such as evaluating
the content of a target property during generation, such
as INCLUDE_DIRECTORIES, the 'head target' is the one on which the
initial request was made.
If evaluating a generator expression which is not a target property
content, the target must be explicitly specified. Such contexts
include add_custom_command and file(GENERATE). The content might
then look like
$<TARGET_PROPERTY:tgt,prop>
However, as there is no HeadTarget set, any generator expressions
evaluated as part of reading prop from tgt which do not specify
the tgt directly report an error.
Modify the logic of the TARGET_PROPERTY generator expression so
that in such contexts, the 'head target' is set to the appropriate
target which was first encountered.
In commit 2bc22bda (Xcode: Add frameworks search paths from link
dependeny closure, 2012-12-07) we made framework search paths from the
link closure conditional on target type, skipping it on STATIC and
OBJECT library targets that do not actually link. However, the
framework search paths also influence the compile lines (-F options) so
we need them for all target types. The Makefile generator already does
this, as did the Xcode generator prior to the above-mentioned commit.
