cmake: disable kits when building statically

ParaView has witnessed that dependency cycles with its Python module
loading strategy during static builds where kits are enabled. To avoid
having this trip up users, just deny the configuration.

CMakeLists.txt

@@ -321,7 +321,10 @@ if ("VTK::Python" IN_LIST vtk_modules)
   endif ()
 endif ()
 
-option(VTK_ENABLE_KITS "Enable kits compilation" OFF)
+cmake_dependent_option(VTK_ENABLE_KITS "Enable kits compilation" OFF
+  # Static builds don't make sense with kits. Ignore the flag if shared
+  # libraries aren't being built.
+  "VTK_BUILD_SHARED_LIBS" OFF)
 mark_as_advanced(VTK_ENABLE_KITS)
 
 option(VTK_USE_EXTERNAL "Use external copies of third party libraries by default" OFF)

Documentation/dev/build.md

@@ -171,9 +171,9 @@ Less common, but variables which may be of interest to some:
     values are `OFF` (no testing), `WANT` (enable tests as possible), and `ON`
     (enable all tests; may error out if features otherwise disabled are
     required by test code).
-  * `VTK_ENABLE_KITS` (default `OFF`): Compile VTK into
-    a smaller set of libraries. Can be useful on platforms where VTK takes a
-    long time to launch due to expensive disk access.
+  * `VTK_ENABLE_KITS` (default `OFF`; requires `BUILD_SHARED_LIBS`): Compile
+    VTK into a smaller set of libraries. Can be useful on platforms where VTK
+    takes a long time to launch due to expensive disk access.
   * `VTK_ENABLE_WRAPPING` (default `ON`): Whether any wrapping support will be
     available or not.
   * `VTK_WRAP_JAVA` (default `OFF`; requires `VTK_ENABLE_WRAPPING`):

Documentation/release/dev/no-static-kits.md

+## no-static-kits
+
+Static builds no longer allow building with kits. The goal of a kit build is to
+reduce the number of runtime libraries needed, but this is not relevant in a
+static build anyways. Additionally, there are issues that arise with static kit
+builds that are lingering and rather than leaving them around for users to
+accidentally run into, VTK now only considers `VTK_ENABLE_KITS` in shared
+builds.