Fix missing MPI dependencies in examples

examples/hello/bpWriter/CMakeLists.txt

@@ -3,8 +3,12 @@
 # accompanying file Copyright.txt for details.
 #------------------------------------------------------------------------------#
 
-add_executable(hello_bpWriter helloBPWriter.cpp)
-target_link_libraries(hello_bpWriter adios2)
+if(ADIOS_USE_MPI)
+  find_package(MPI COMPONENTS C REQUIRED)
+  add_executable(hello_bpWriter helloBPWriter.cpp)
+  target_include_directories(hello_bpWriter ${MPI_C_INCLUDE_PATH})
+  target_link_libraries(hello_bpWriter adios2 ${MPI_C_LIBRARIES})
+endif()
 
 add_executable(hello_bpWriter_nompi helloBPWriter_nompi.cpp)
 target_link_libraries(hello_bpWriter_nompi adios2)

examples/hello/timeBP/CMakeLists.txt

@@ -3,8 +3,14 @@
 # accompanying file Copyright.txt for details.
 #------------------------------------------------------------------------------#
 
-add_executable(hello_timeBPWriter timeBPWriter.cpp)
-target_link_libraries(hello_timeBPWriter adios2)
+if(ADIOS_USE_MPI)
+  find_package(MPI COMPONENTS C REQUIRED)
+  add_executable(hello_timeBPWriter timeBPWriter.cpp)
+  target_link_libraries(hello_timeBPWriter adios2)
+  target_include_directories(hello_timeBPWriter ${MPI_C_INCLUDE_PATH})
+  target_link_libraries(hello_timeBPWriter adios2 ${MPI_C_LIBRARIES})
+endif()
+
 
 add_executable(hello_timeBPWriter_nompi timeBPWriter_nompi.cpp)
 target_link_libraries(hello_timeBPWriter_nompi adios2)