Add ADIOS2 option to Trilinos (spack#11609)

ADIOS2 is the latest implementation of the ADaptable Input Output System,
ADIOS. This brand new architecture was designed to continue supporting the
performance legacy of ADIOS, and extend its current capabilities to address
current and future input/output (IO) challenges in the scientific data
lifecycle through effective research and development (R&D) activities.

ADIOS2 was recently added as a Third Party Library of Trilinos when it
was integrated to IOSS, a library inside the SEACAS package.

var/spack/repos/builtin/packages/trilinos/package.py

@@ -81,6 +81,8 @@ class Trilinos(CMakePackage):
             description='Compile with Boost')
     variant('cgns',         default=False,
             description='Enable CGNS')
+    variant('adios2',         default=False,
+            description='Enable ADIOS2')
     variant('gtest',        default=True,
             description='Compile with Gtest')
     variant('hdf5',         default=True,
@@ -276,7 +278,9 @@ class Trilinos(CMakePackage):
         '+shared', when='+stk platform=darwin',
         msg='Cannot build Trilinos with STK as a shared library on Darwin.'
     )
-
+    # ADIOS2 was only added after v12.14.1
+    conflicts('+adios2', when='@:12.14.1')
+    conflicts('+adios2', when='@xsdk-0.2.0')
     # ###################### Dependencies ##########################
 
     # Everything should be compiled position independent (-fpic)
@@ -297,6 +301,7 @@ class Trilinos(CMakePackage):
     depends_on('parallel-netcdf', when="+pnetcdf@master,12.12.1:")
     depends_on('parmetis', when='+metis')
     depends_on('cgns', when='+cgns')
+    depends_on('adios2', when='+adios2')
     # Trilinos' Tribits config system is limited which makes it very tricky to
     # link Amesos with static MUMPS, see
     # https://trilinos.org/docs/dev/packages/amesos2/doc/html/classAmesos2_1_1MUMPS.html
@@ -674,6 +679,7 @@ def cmake_args(self):
                 '-DTPL_ENABLE_CGNS:BOOL=OFF'
             ])
 
+        options.append('-DTPL_ENABLE_ADIOS2:BOOL=' + str('+adios2' in spec))
         # ################# Miscellaneous Stuff ######################
 
         # OpenMP