Fix include errors for iphreeqc.

ThirdParty/CMakeLists.txt

@@ -15,6 +15,9 @@ if (OGS_BUILD_PROCESS_ComponentTransport
     OR OGS_BUILD_PROCESS_HeatTransportBHE)
     add_subdirectory(iphreeqc)
     list(APPEND DISABLE_WARNINGS_TARGETS iphreeqc)
+    target_include_directories(iphreeqc SYSTEM PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/iphreeqc/src/src/phreeqcpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/iphreeqc/src/src/phreeqcpp/common)
 endif()
 
 # MFrontGenericInterfaceSupport