Support implibs for executables on Windows

Add a boolean 'implib' kwarg to executable().  If true, it is permitted to
use the returned build target object in link_with:

On platforms where this makes sense (e.g. Windows), an implib is generated
for the executable and used when linking.  Otherwise, it has no effect.

(Rather than checking if it is a StaticLibrary or SharedLibary, BuildTarget
subclasses gain the is_linkable_target method to test if they can appear in
link_with:)

Also install any executable implib in a similar way to a shared library
implib, i.e. placing the implib in the appropriate place

Add tests of:
- a shared_module containing a reference to a symbol which is known (at link
time) to be provided by the executable
- trying to link with non-implib executables (should fail)
- installing the implib

(This last one needs a little enhancement of the installed file checking as
this is the first install test we have which needs to work with either
MSVC-style or GCC-style implib filenames)

1 files changed, 1 insertions, 0 deletions

diff --git a/docs/markdown/Reference-manual.md b/docs/markdown/Reference-manual.md
index e45adf6..261d898 100644
--- a/docs/markdown/Reference-manual.md
+++ b/docs/markdown/Reference-manual.md
@@ -248,6 +248,7 @@ Executable supports the following keyword arguments. Note that just like the pos
 - `name_suffix` the string that will be used as the extension for the target by overriding the default. By default on Windows this is `exe` and on other platforms it is omitted.
 - `build_by_default` causes, when set to true, to have this target be built by default, that is, when invoking plain `ninja`, the default value is true for all built target types, since 0.38.0
 - `override_options` takes an array of strings in the same format as `project`'s `default_options` overriding the values of these options for this target only, since 0.40.0
+- `implib` when set to true, an import library is generated for the executable, used when the returned build target object appears elsewhere in `link_with:`, on platforms where this is meaningful (e.g. Windows), since 0.42.0
 
 The list of `sources`, `objects`, and `dependencies` is always flattened, which means you can freely nest and add lists while creating the final list. As a corollary, the best way to handle a 'disabled dependency' is by assigning an empty list `[]` to it and passing it like any other dependency to the `dependencies:` keyword argument.