[cmake] Silence spdlog warnings.

Applications/DataExplorer/DataExplorer.cmake

@@ -40,7 +40,7 @@ target_link_libraries(
     Qt5::Widgets
     Qt5::Xml
     Qt5::Network
-    spdlog::spdlog
+    spdlog
     VTK::IOExport
 )
 

BaseLib/CMakeLists.txt

@@ -11,7 +11,7 @@ ogs_add_library(BaseLib GENERATE_EXPORT_HEADER ${SOURCES})
 target_link_libraries(
     BaseLib
     PUBLIC Boost::boost
-           spdlog::spdlog
+           spdlog
            tclap
            $<$<BOOL:${MSVC}>:WinMM> # needed for timeGetTime
            $<$<BOOL:${OGS_BUILD_GUI}>:Qt5::Xml>

scripts/cmake/CheckHeaderCompilation.cmake

@@ -44,7 +44,7 @@ function(_check_header_compilation target)
     endif()
     get_target_property(LINK_LIBS ${target} LINK_LIBRARIES)
     # Transitive dependencies are not resolved
-    foreach(lib ${LINK_LIBS} spdlog::spdlog Boost::boost Eigen3::Eigen
+    foreach(lib ${LINK_LIBS} spdlog Boost::boost Eigen3::Eigen
                 nlohmann_json::nlohmann_json range-v3
     )
         # Ignore non-existing targets or interface libs

scripts/cmake/Dependencies.cmake

@@ -50,7 +50,19 @@ if(OGS_BUILD_TESTING)
     endif()
 endif()
 
-CPMFindPackage(NAME spdlog GITHUB_REPOSITORY gabime/spdlog VERSION 1.10.0)
+CPMFindPackage(
+    NAME spdlog
+    GITHUB_REPOSITORY gabime/spdlog
+    VERSION 1.10.0
+    OPTIONS "BUILD_SHARED_LIBS OFF" "SPDLOG_BUILD_SHARED OFF"
+)
+if(spdlog_ADDED)
+    set_target_properties(
+        spdlog
+        PROPERTIES INTERFACE_SYSTEM_INCLUDE_DIRECTORIES
+                   $<TARGET_PROPERTY:spdlog,INTERFACE_INCLUDE_DIRECTORIES>
+    )
+endif()
 
 CPMFindPackage(
     NAME tclap