When linking with cmake and vs_link_* the command line
could be too long for cmd.exe, which needs not to be
called in this case. (was not cached by a test)
Introduce rules which don't use the shell and use this
rule when there are no pre or post step.
For free we get a small speedup, because cmd is then
not called.
Also be more accurate when estimating the
command line length.
cmcldeps wraps cl and adds /showInclude before calling cl.
It parses the output of cl for used headers, drops system
headers and writes them to a GCC like dependency file.
cmcldeps uses ATM ninja code for process handling,
but could be ported later to SystemTools.
TODO: Why needs ninja multiple calls in the BuildDepends test?
When MinGW is used slashes are used for dependencies
because ar.exe can't read rsp files with backslashes.
Many thx to Claus Klein for starting working on this.
Implement cmGlobalGenerator::ComputeTargetObjects in the Ninja generator
to pre-compute all the object file names. Use the results during
generation instead of re-computing it later.
Generally these are only required in build statements, as Ninja wants
to be able to chop paths up. But it doesn't hurt to also try to use
them in command line arguments.