--- tmva/tmva/CMakeLists.txt.orig	2023-02-13 15:54:54 UTC
+++ tmva/tmva/CMakeLists.txt
@@ -444,15 +444,20 @@ if(tmva-cpu)
   target_link_libraries(TMVA PRIVATE ${TBB_LIBRARIES})
   set_target_properties(TMVA PROPERTIES COMPILE_FLAGS "${TBB_CXXFLAGS}")
 
-  if(BLAS_FOUND)
-    target_link_libraries(TMVA PRIVATE ${BLAS_LINKER_FLAGS} ${BLAS_LIBRARIES})
-  elseif(GSL_FOUND)
+  # Port maintainer note: Prefer GSL's BLAS over OpenBLAS since GSL is a basic port dependency, 
+  # but OpenBLAS can only be assumed available when PyROOT (which requires NumPy) is enabled.
+  # GSL does not depend on GCC, but NumPy depends on OpenBLAS which depends on GCC.
+  # By preferring GSL, we can entirely avoid depending on GCC in some build cases.
+  if(GSL_FOUND)
     target_compile_definitions(TMVA PRIVATE -DDNN_USE_CBLAS)
     target_include_directories(TMVA SYSTEM PRIVATE ${GSL_INCLUDE_DIR})
     target_link_libraries(TMVA PRIVATE ${GSL_CBLAS_LIBRARY})
     if(builtin_gsl)
       add_dependencies(TMVA GSL)
     endif()
+  elseif(BLAS_FOUND)
+    target_link_libraries(TMVA PRIVATE ${BLAS_LINKER_FLAGS} ${BLAS_LIBRARIES})
+  
   else()
     message(FATAL_ERROR "tmva-cpu enabled but neither BLAS nor GSL BLAS were found")
   endif()
