Remove explicit Boost::system dependency from our cmake

Boost::system is only used transitively by the other Boost libraries, so
their CMake will include it when it is needed.

CMakeLists.txt

@@ -779,7 +779,7 @@ set( BOOST_REQUESTED_COMPONENTS locale )    # locale is required by nanoodbc/dat
 
 if( KICAD_BUILD_QA_TESTS )
     # required by the unit test framework
-    list( APPEND BOOST_REQUESTED_COMPONENTS unit_test_framework system )
+    list( APPEND BOOST_REQUESTED_COMPONENTS unit_test_framework )
 endif()
 
 find_package( Boost 1.71.0 REQUIRED COMPONENTS ${BOOST_REQUESTED_COMPONENTS} )

qa/tools/libeval_compiler/CMakeLists.txt

@@ -76,6 +76,5 @@ target_link_libraries( libeval_compiler_test
     pcbcommon
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${wxWidgets_LIBRARIES}
 )

qa/tools/pcb_test_window/CMakeLists.txt

@@ -66,6 +66,5 @@ target_link_libraries( test_window
     ${PCBNEW_IO_LIBRARIES}
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${wxWidgets_LIBRARIES}
 )

qa/unittests/common/CMakeLists.txt

@@ -86,7 +86,6 @@ target_link_libraries( qa_common
     qa_utils
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${wxWidgets_LIBRARIES}
     )
 

qa/unittests/eeschema/CMakeLists.txt

@@ -132,7 +132,6 @@ PRIVATE
     ${GDI_PLUS_LIBRARIES}
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
 )
 
 if( KICAD_SPICE AND KICAD_SPICE_QA AND MSVC )

qa/unittests/gerbview/CMakeLists.txt

@@ -70,7 +70,6 @@ target_link_libraries( qa_gerbview
     ${PYTHON_LIBRARIES}
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${PCBNEW_EXTRA_LIBS}    # -lrt must follow Boost
 )
 

qa/unittests/libs/kimath/CMakeLists.txt

@@ -72,7 +72,6 @@ target_link_libraries( qa_kimath
     kimath
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${wxWidgets_LIBRARIES}
 )
 

qa/unittests/libs/sexpr/CMakeLists.txt

@@ -36,7 +36,6 @@ target_link_libraries( qa_sexpr
     qa_utils
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${wxWidgets_LIBRARIES}
 )
 

qa/unittests/pcbnew/CMakeLists.txt

@@ -120,7 +120,6 @@ target_link_libraries( qa_pcbnew
     ${PYTHON_LIBRARIES}
     Boost::headers
     Boost::unit_test_framework
-    Boost::system
     ${PCBNEW_EXTRA_LIBS}    # -lrt must follow Boost
 )