Merge pull request #70 from chuckatkins/fix-adios1-env-var-check

Fix borked logic for testing ADIOS1 env vars

cmake/FindADIOS1.cmake

@@ -107,7 +107,7 @@ set(adios1_config_hints)
 foreach(PREFIX_VAR IN ITEMS ADIOS1_ROOT ADIOS1_DIR INSTALL_PREFIX)
   if(${PREFIX_VAR})
     list(APPEND adios1_config_hints "${${PREFIX_VAR}}/bin")
-  elseif("$ENV{${PREFIX_VAR}}")
+  elseif(NOT ("$ENV{${PREFIX_VAR}}" STREQUAL ""))
     list(APPEND adios1_config_hints "$ENV{${PREFIX_VAR}}/bin")
   endif()
 endforeach()