cmake: Update cpptrace include dir for install

Author: ZedThree

CMakeLists.txt

@@ -818,6 +818,9 @@ endif()
 if (NOT BOUT_USE_SYSTEM_FMT)
   set(FMT_INCLUDE_PATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
 endif()
+if (NOT BOUT_USE_SYSTEM_CPPTRACE)
+  set(CPPTRACE_INCLUDE_PATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
 set(BOUT_INCLUDE_PATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
 # We don't need the build include path any more
 string(REPLACE "-I${CMAKE_CURRENT_BINARY_DIR}/include" "" CONFIG_CFLAGS "${CONFIG_CFLAGS}")