Add the handling of the CTEST_PARALLEL_LEVEL env var.
Merge topic 'ctest-parallel-env' into next

60c412a Add the handling of the CTEST_PARALLEL_LEVEL env var.
Fix brace indentation.
Merge topic 'fix-style' into next

3c7c332 Fix brace indentation.
Add EXPORT_NAME property.

This allows for example, the buildsystem to use names like 'boost_any'
instead of the overly generic 'any', and still be able to generate
IMPORTED targets called 'boost::any'.
Merge topic 'add-EXPORT_NAME-property' into next

d3879a4 Add EXPORT_NAME property.
Add EXPORT_NAME property.

This allows for example, the buildsystem to use names like 'boost_any'
instead of the overly generic 'any', and still be able to generate
IMPORTED targets called 'boost::any'.
Merge topic 'add-EXPORT_NAME-property' into next

b5d6f5d Add EXPORT_NAME property.
Add $<LINK_LANGUAGE> generator expressions.

They can't be used when evaluating link libraries, but they can be
used for include directories and compile definitions. Later they can
be used for compile options.
Merge topic 'language-generator-expressions' into next

95c85ab Add $<LINK_LANGUAGE> generator expressions.
Exclude some systems which don't seem to work with C only.
Merge topic 'generate_export_header-fixes' into next

20e820b Exclude some systems which don't seem to work with C only.