readme.txt: fix typo

Alex
find_package(): add support for a <package>_NOT_FOUND_MESSAGE variable

If a config-file sets <package>_FOUND to FALSE, it can now give a reason
using the variable <package>_NOT_FOUND_MESSAGE, which is used by cmFindPackage
and FPHSA.

Alex
Move cmTargetExport to a dedicated header file
Remove cmTargetExport constructor

The constructor was used exactly once.
Setting members explicitly makes the code more readable.
Rename cmGlobalGenerator::AddTargetToExport{s,}

This function adds target to one export, not to several exports.
Create ExportSet class
Add cmExportSetMap class

This is a map<string, cmExportSet *> with overloaded operator[] and destructor.
cm*Export*Generator: hold a pointer to ExportSet

Get name from this->ExportSet.
No need to explicitly clear ExportSets, will be cleared in destructor

TODO: remove another clear() because it doesn't delete TargetExports.
export sets: store pointers to all installations of this export set

This information will be used to check whether a target is exported
once or multiple times and to check its namespace.

Alex
cmGlobalGenerator.h: some minor coding style fixes

- this-> was missing in two places
- removed unnecessary semicolons
- indented unindented lines

Alex
export sets: accept a missing target if it is exported exactly once

If a target is exported, and a library it depends on is not part
of the same export set, before this patch cmake errored out.
With this patch, it now checks whether the missing target
is exported somewhere else exactly once, and accepts in this
case (because then it can determine the namespace for the
missing target and use this).

Alex
export sets: first try at error handling if a target is missing

Now, if an imported target depends on a library which must come
from some other export set, cmake generates a check which errors
out if that target does not exist. I guess instead of completely
erroring out it would be better to only make the find_package() fail.

Alex
export sets: make the test succeed

Now with the error message if a required imported target does not exist,
the order how the target-files are included matters.
So I think fixing the test (instead of changing the code) is ok.

But this also shows that this error may break existing stuff I think...

Alex
export sets: define a CMAKE_FIND_PACKAGE_NAME var set by find_package()

This way the name of the searched package can be accessed in find-modules,
config-files and more importantly in generated target export files.
This is now used when a target export file detects that a required
target does not exist.

Alex
export-sets: add a test for exporting dependent targets

The test exports two libraries into two separate exports,
and then include()s the generated export files. This must not fail.

Alex
Merge topic 'AutomocUseTargetProperties' into export-sets-2

Conflicts:
	Source/cmGlobalGenerator.h
Merge topic 'generator-expression-target-properties' into export-sets-2
Merge topic 'export-sets-2' into next

962763d Merge topic 'generator-expression-target-properties' into export-sets-2
a1dd07a Merge topic 'AutomocUseTargetProperties' into export-sets-2
3eb23ed export-sets: add a test for exporting dependent targets
554a379 export sets: define a CMAKE_FIND_PACKAGE_NAME var set by find_package()
21d1619 export sets: make the test succeed
9aff151 export sets: first try at error handling if a target is missing
2006296 export sets: accept a missing target if it is exported exactly once
96f3e75 cmGlobalGenerator.h: some minor coding style fixes
9571e3a export sets: store pointers to all installations of this export set
eca7827 No need to explicitly clear ExportSets, will be cleared in destructor
70c9db5 cm*Export*Generator: hold a pointer to ExportSet
323770f Add cmExportSetMap class
12c8665 Create ExportSet class
17a21af Rename cmGlobalGenerator::AddTargetToExport{s,}
c3669b0 Remove cmTargetExport constructor
ffe2d9c Move cmTargetExport to a dedicated header file
...