Clean up MCPL references (#3927)

Author: tjlaboss

docs/source/usersguide/install.rst

@@ -331,11 +331,11 @@ Prerequisites
 
       This option allows OpenMC to read and write MCPL (Monte Carlo Particle
       Lists) files instead of .h5 files for sources (external source
-      distribution, k-eigenvalue source distribution, and surface sources). To
-      turn this option on in the CMake configuration step, add the following
-      option::
-
-          cmake -DOPENMC_USE_MCPL=on ..
+      distribution, k-eigenvalue source distribution, and surface sources). 
+      OpenMC does not need any particular build option to use this, but MCPL
+      must be installed on the system in order to do so. Refer to the 
+      `MCPL documentation <https://github.com/mctools/mcpl/blob/HEAD/INSTALL.md>`_
+      for instructions on how to accomplish this.
 
     * NCrystal_ library for defining materials with enhanced thermal neutron transport
 

src/output.cpp

@@ -321,7 +321,6 @@ void print_build_info()
   std::string png(n);
   std::string profiling(n);
   std::string coverage(n);
-  std::string mcpl(n);
   std::string uwuw(n);
   std::string strict_fp(n);
 
@@ -337,9 +336,6 @@ void print_build_info()
 #ifdef OPENMC_LIBMESH_ENABLED
   libmesh = y;
 #endif
-#ifdef OPENMC_MCPL
-  mcpl = y;
-#endif
 #ifdef USE_LIBPNG
   png = y;
 #endif
@@ -369,7 +365,6 @@ void print_build_info()
     fmt::print("PNG support:           {}\n", png);
     fmt::print("DAGMC support:         {}\n", dagmc);
     fmt::print("libMesh support:       {}\n", libmesh);
-    fmt::print("MCPL support:          {}\n", mcpl);
     fmt::print("Coverage testing:      {}\n", coverage);
     fmt::print("Profiling flags:       {}\n", profiling);
     fmt::print("UWUW support:          {}\n", uwuw);