Attempt to get Petsc build with static library

This adds the private libs to the petsc link line. It *should* work even
if petsc built as a shared library.

Author: jacobmerson

src/pcms/transfer/CMakeLists.txt

@@ -48,7 +48,7 @@ target_link_libraries(pcms_transfer PUBLIC
 
 target_link_libraries(pcms_transfer PUBLIC meshfields::meshfields)
 
-target_link_libraries(pcms_transfer PUBLIC PkgConfig::PETSC)
+target_link_libraries(pcms_transfer PRIVATE PkgConfig::PETSC)
 
 target_include_directories(pcms_transfer INTERFACE
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>

test/CMakeLists.txt

@@ -415,11 +415,7 @@ if(Catch2_FOUND)
   #   target_link_libraries(unit_tests PUBLIC meshfields::meshfields)
   # endif()
 
-  # if (PCMS_ENABLE_PETSC)
-  #  # TODO, update to pkgconfig target instead
-  #  target_include_directories(unit_tests PUBLIC ${PCMS_PETSC_INCLUDES})
-  #  target_link_libraries(unit_tests PUBLIC ${PCMS_PETSC_LIBRARIES})
-  #endif()
+  target_link_libraries(unit_tests PRIVATE PkgConfig::PETSC)
 
   target_link_libraries(unit_tests PUBLIC 
     Catch2::Catch2