Force removing of .gcda files to avoid merging of obsolete files

These merge could generate coverage failures
One should use cmake commands instead of unix find+rm for portability

CMakeLists.txt

@@ -250,9 +250,16 @@ if("${CMAKE_BUILD_TYPE}" STREQUAL "Coverage")
 
   set(GCOVR_OPTIONS --object-directory="${PUGS_BINARY_DIR}" -r "${PUGS_SOURCE_DIR}/src" ${GCOVR_EXCLUDE} ${GCOVR_EXTRA})
 
+  add_custom_target(coverage-clean-up
+    ALL
+    COMMAND find "${PUGS_BINARY_DIR}" -name \*.gcda -exec rm -f {} +;
+    COMMENT "Removing obsolete gcda to perform a net coverage."
+    )
+
   add_custom_target(coverage
     ALL
     COMMAND ${GCOVR} ${GCOVR_OPTIONS} --exclude-unreachable-branches --sort-percentage
+    DEPENDS coverage-clean-up
     DEPENDS run_unit_tests pugs
     COMMENT "Running gcovr to build coverage report."
     )