Remove system headers when preprocessing coverage report
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef02c13..9d667e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -306,7 +306,7 @@
 
     if (ENABLE_COVERAGE)
         add_coverage(SelfTest)
-        list(APPEND LCOV_REMOVE_PATTERNS "/sys/")
+        list(APPEND LCOV_REMOVE_PATTERNS "/usr/")
         coverage_evaluate()
     endif()