Merge pull request #4078 from jwpeterson/fix_transient_ex3_disable_optional

transient_ex3 requires a solver

Author: jwpeterson

examples/transient/transient_ex3/transient_ex3.C

@@ -43,6 +43,7 @@
 #include "libmesh/exodusII_io.h"
 #include "libmesh/equation_systems.h"
 #include "libmesh/getpot.h"
+#include "libmesh/enum_solver_package.h"
 
 // Application includes
 #include "advection_system.h"
@@ -67,6 +68,10 @@ int main (int argc, char** argv)
   // Initialize libMesh.
   LibMeshInit init (argc, argv);
 
+  // This example requires a linear solver package.
+  libmesh_example_requires(libMesh::default_solver_package() != INVALID_SOLVER_PACKAGE,
+                           "--enable-petsc, --enable-trilinos, or --enable-eigen");
+
   // Create GetPot object to parse the command line
   GetPot command_line (argc, argv);