cmTarget: Remove some hardcoding of transitive property names.
VS6: Rename some variables to correspond to config values.

This simplifies population of the compile flags.
Add cmLocalGenerator::GetCompileOptions.

Currently it only adds the contents of the COMPILE_FLAGS target
property, but it can be extended to handle a new COMPILE_OPTIONS
generator expression enabled property.
Add <LANG>_COMPILER_ID generator expressions.

These expressions evaluate to the id of the compiler used to build
the target, or can be used to test if the compiler id matches a
specified value.
cmTarget: Rename struct to be more re-usable.

The same struct can be used to represent COMPILE_OPTIONS content.
Add COMPILE_OPTIONS target property.

This method reads generator expressions from the COMPILE_OPTIONS
target property, as well as INTERFACE_COMPILE_OPTIONS from linked
dependents.
cmTarget: Rename LinkInterfaceIncludeDirectoriesEntries

This can be used for COMPILE_OPTIONS too.
Add target_compile_options command.

This command populates the COMPILE_OPTIONS target property.
Merge topic 'target-COMPILE_OPTIONS' into next

a70c00a Add target_compile_options command.
72332e4 Add COMPILE_OPTIONS target property.
68b7593 cmTarget: Rename LinkInterfaceIncludeDirectoriesEntries
6437377 cmTarget: Rename struct to be more re-usable.
ecedf6e Add <LANG>_COMPILER_ID generator expressions.
0476d7e Add cmLocalGenerator::GetCompileOptions.
f418fed VS6: Rename some variables to correspond to config values.
db298ff cmTarget: Remove some hardcoding of transitive property names.
Test with a platform independent define instead of a -f flag.
Merge topic 'target-COMPILE_OPTIONS' into next

0368b74 Test with a platform independent define instead of a -f flag.
Add COMPILE_OPTIONS target property.

This method reads generator expressions from the COMPILE_OPTIONS
target property, as well as INTERFACE_COMPILE_OPTIONS from linked
dependents.
Add target_compile_options command.

This command populates the COMPILE_OPTIONS target property.
Merge topic 'target-COMPILE_OPTIONS' into next

f4c1723 Add target_compile_options command.
fab5b0c Add COMPILE_OPTIONS target property.