Update VisIt to version 3.0.1 and fix on mac (#12396)

* Add option to disable QTDesigner plugin for qwt

Qt designer shouldn't be necessary to build downstream GUI code.
Currently `qwt^qt~tools` fails to build:

(darwin clang@10.0.1)
```
compiling qwt_designer_plugin.cpp
compiling qwt_designer_plotdialog.cpp
moc qwt_designer_plugin.h
moc qwt_designer_plotdialog.h
rcc qwt_designer_plugin.qrc
qwt_designer_plugin.h:23: Error: Undefined interface
make[1]: *** [moc/moc_qwt_designer_plugin.cpp] Error 1
make[1]: *** Waiting for unfinished jobs....
qwt_designer_plugin.cpp:17:10: fatal error: 'QDesignerFormEditorInterface' file not found
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[1]: *** [obj/qwt_designer_plugin.o] Error 1
make: *** [sub-designer-make_default-ordered] Error 2
```

* Update VTK for newer VisIt and compiler versions

Several changes/enhancements to VTK package

---

Add version 8.1.0 (default version for VisIt 3.x)

---

Tweak VTK options for version 8 and VisIt:

- only add mpi4py version option when mpi4py is enabled
- Require object factory for downstream packages
- Remove OpenGL preference for VTK 8

---

Combine +python3 into +python

The spec for using python3 should just be `+python^python@3:`.

---

Remove unused VTK cmake argument on newer version

---

Patch for Python 3 fails on VTK 6.1 (needed for VisIt 2.x):
```
==> Patch /rnsdhpc/code/spack/var/spack/repos/builtin/packages/vtk/python3.7-const-char.patch failed.
==> Error: ProcessError: Command exited with status 1:
    '/usr/bin/patch' '-s' '-p' '1' '-i' '/rnsdhpc/code/spack/var/spack/repos/builtin/packages/vtk/python3.7-const-char.patch' '-d' '.'
```

and as it happens, VisIt 2.13 is incompatible with Python 3 anyway.

---

Fix compiler error:

As spack's configuration warning says, double-quotes can cause trouble:
```
==> [2019-07-29-11:47:55.269653] Warning: Quotes in command arguments can confuse scripts like configure.
  The following arguments may cause problems when executed:
      -DVTK_REQUIRED_OBJCXX_FLAGS=""
  Quotes aren't needed because spack doesn't use a shell.
  Consider removing them
```
They were being added to the compile line, causing clang to think it was
asked to compile an empty file:
```
cd /private/var/folders/fy/x2xtwh1n7fn0_0q2kk29xkv9vvmbqb/T/s3j/spack-stage/spack-stage-3nk9bwe_/spack-build/Rendering/OpenGL && /rnsdhpc/code/spack/lib/spack/env/clang/clang++  -DVTK_IN_VTK -DvtkRenderingOpenGL_EXPORTS -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks  -DGLX_GLXEXT_LEGACY  -O2 -g -DNDEBUG -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -fPIC   -fvisibility=hidden -fvisibility-inlines-hidden "" -o CMakeFiles/vtkRenderingOpenGL.dir/vtkCocoaGLView.mm.o -c /rnsdhpc/code/spack/var/spack/stage/vtk-6.1.0-b2mj276iz77fadisv2me365qe27t3gxt/spack-src/Rendering/OpenGL/vtkCocoaGLView.mm
clang: error: no input files
make[2]: *** [Rendering/OpenGL/CMakeFiles/vtkRenderingOpenGL.dir/vtkCocoaGLView.mm.o] Error 1
```

* Modernize/PEP-8 visit package statements

* Add new VisIt version and patches for building on Mac

- VisIt's cmake assumes a 'vtk(tiff|jpeg|png)' *library* target exported by
  VTK, but VTK 8.1.x on my configuration seems to have these as header-only
  targets with library dependencies.
- Explicitly add QT path to visit configure: Without this, somehow
  `${VISIT_QT_DIR}` was being set to empty, so that the build failed with
  `missing /bin/moc`.
- VisIt assumes that if it isn't being built statically, QWT has been built as
  a mac Framework. QWT actually is built as a framework based on whether QT
  itself is.

Error message:
```
-- Looking for QWT
CMake Error at CMake/SetUpThirdParty.cmake:131 (MESSAGE):
    Include Directory for QWT (/rnsdhpc/code/spack/opt/spack/darwin-mojave-x86_64/clang-10.0.1-apple/qwt-6.1.3-bmfxirweplzhjoiil4rw632evkyteuwk/lib/qwt.framework/Versions/Current/Headers) does not exist.
Call Stack (most recent call first):
  CMake/FindQwt.cmake:57 (SET_UP_THIRD_PARTY)
  CMakeLists.txt:1251 (INCLUDE)
```

1 files changed, 19 insertions, 20 deletions

diff --git a/var/spack/repos/builtin/packages/vtk/package.py b/var/spack/repos/builtin/packages/vtk/package.py
index 82cd423e4f..1be771e9f4 100644
--- a/var/spack/repos/builtin/packages/vtk/package.py
+++ b/var/spack/repos/builtin/packages/vtk/package.py
@@ -22,6 +22,7 @@ class Vtk(CMakePackage):
 
     version('8.1.2', sha256='0995fb36857dd76ccfb8bb07350c214d9f9099e80b1e66b4a8909311f24ff0db')
     version('8.1.1', sha256='71a09b4340f0a9c58559fe946dc745ab68a866cf20636a41d97b6046cb736324')
+    version('8.1.0', sha256='6e269f07b64fb13774f5925161fb4e1f379f4e6a0131c8408c555f6b58ef3cb7')
     version('8.0.1', '692d09ae8fadc97b59d35cab429b261a')
     version('7.1.0', 'a7e814c1db503d896af72458c2d0228f')
     version('7.0.0', '5fe35312db5fb2341139b8e4955c367d')
@@ -32,7 +33,6 @@ class Vtk(CMakePackage):
     variant('opengl2', default=True, description='Enable OpenGL2 backend')
     variant('osmesa', default=False, description='Enable OSMesa support')
     variant('python', default=False, description='Enable Python support')
-    variant('python3', default=False, description='Enable Python3 support')
     variant('qt', default=False, description='Build with support for Qt')
     variant('xdmf', default=False, description='Build XDMF file support')
     variant('ffmpeg', default=False, description='Build with FFMPEG support')
@@ -43,21 +43,16 @@ class Vtk(CMakePackage):
     # At the moment, we cannot build with both osmesa and qt, but as of
     # VTK 8.1, that should change
     conflicts('+osmesa', when='+qt')
-    conflicts('+python', when='+python3')
-    conflicts('+python3', when='@:8.0')
+    conflicts('^python@3:', when='@:8.0')
 
     extends('python', when='+python')
-    extends('python', when='+python3')
-
-    depends_on('python@2.7:2.8', when='+python', type=('build', 'run'))
-    depends_on('python@3:', when='+python3', type=('build', 'run'))
 
+    depends_on('python@2.7:', when='+python', type=('build', 'run'))
     depends_on('py-mpi4py', when='+python+mpi', type='run')
-    depends_on('py-mpi4py', when='+python3+mpi', type='run')
 
     # python3.7 compatibility patch backported from upstream
     # https://gitlab.kitware.com/vtk/vtk/commit/706f1b397df09a27ab8981ab9464547028d0c322
-    patch('python3.7-const-char.patch', when='@:8.1.1 ^python@3.7:')
+    patch('python3.7-const-char.patch', when='@7.0.0:8.1.1 ^python@3.7:')
 
     # The use of the OpenGL2 backend requires at least OpenGL Core Profile
     # version 3.2 or higher.
@@ -129,6 +124,9 @@ class Vtk(CMakePackage):
             '-DNETCDF_C_ROOT={0}'.format(spec['netcdf'].prefix),
             '-DNETCDF_CXX_ROOT={0}'.format(spec['netcdf-cxx'].prefix),
 
+            # Allow downstream codes (e.g. VisIt) to override VTK's classes
+            '-DVTK_ALL_NEW_OBJECT_FACTORY:BOOL=ON',
+
             # Disable wrappers for other languages.
             '-DVTK_WRAP_JAVA=OFF',
             '-DVTK_WRAP_TCL=OFF',
@@ -144,12 +142,13 @@ class Vtk(CMakePackage):
             cmake_args.extend(['-DModule_vtkIOFFMPEG:BOOL=ON'])
 
         # Enable/Disable wrappers for Python.
-        if '+python' in spec or '+python3' in spec:
+        if '+python' in spec:
             cmake_args.extend([
                 '-DVTK_WRAP_PYTHON=ON',
                 '-DPYTHON_EXECUTABLE={0}'.format(spec['python'].command.path),
-                '-DVTK_USE_SYSTEM_MPI4PY:BOOL=ON'
             ])
+            if '+mpi' in spec:
+                cmake_args.append('-DVTK_USE_SYSTEM_MPI4PY:BOOL=ON')
         else:
             cmake_args.append('-DVTK_WRAP_PYTHON=OFF')
 
@@ -206,12 +205,10 @@ class Vtk(CMakePackage):
             if '+mpi' in spec:
                 cmake_args.extend(["-DModule_vtkIOParallelXdmf3:BOOL=ON"])
 
-        cmake_args.extend([
-            '-DVTK_USE_SYSTEM_GLEW:BOOL=ON',
+        cmake_args.append('-DVTK_RENDERING_BACKEND:STRING=' + opengl_ver)
 
-            '-DVTK_RENDERING_BACKEND:STRING=OpenGL{0}'.format(
-                '2' if '+opengl2' in spec else ''),
-        ])
+        if spec.satisfies('@:8.1.0'):
+            cmake_args.append('-DVTK_USE_SYSTEM_GLEW:BOOL=ON')
 
         if '+osmesa' in spec:
             cmake_args.extend([
@@ -220,9 +217,10 @@ class Vtk(CMakePackage):
                 '-DVTK_OPENGL_HAS_OSMESA:BOOL=ON'])
 
         else:
-            cmake_args.extend([
-                '-DVTK_OPENGL_HAS_OSMESA:BOOL=OFF',
-                '-DOpenGL_GL_PREFERENCE:STRING=LEGACY'])
+            cmake_args.append('-DVTK_OPENGL_HAS_OSMESA:BOOL=OFF')
+            if spec.satisfies('@:7.9.9'):
+                # This option is gone in VTK 8.1.2
+                cmake_args.append('-DOpenGL_GL_PREFERENCE:STRING=LEGACY')
 
             if 'darwin' in spec.architecture:
                 cmake_args.extend([
@@ -262,10 +260,11 @@ class Vtk(CMakePackage):
             if (self.spec.satisfies('%clang') and
                 self.compiler.is_apple and
                 self.compiler.version >= Version('5.1.0')):
-                cmake_args.extend(['-DVTK_REQUIRED_OBJCXX_FLAGS=""'])
+                cmake_args.extend(['-DVTK_REQUIRED_OBJCXX_FLAGS='])
 
             # A bug in tao pegtl causes build failures with intel compilers
             if '%intel' in spec and spec.version >= Version('8.2'):
                 cmake_args.append(
                     '-DVTK_MODULE_ENABLE_VTK_IOMotionFX:BOOL=OFF')
+
         return cmake_args