Properly fix #840

The problem was probably caused by
the absence of -lgcov as a linker option.
With this I'm replacing
-fprofile-arcs -ftest-coverage and the linker options
with --coverage, that passes all the correct flags
to compiler and linker.

CMakeLists.txt

@@ -19,7 +19,12 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/CMakeModules)
 include(CheckAtomic)
 
 if(CMAKE_BUILD_TYPE MATCHES "Debug")
-    add_compile_options(-g -Og -ftest-coverage -fstack-protector-all --param=ssp-buffer-size=4)
+    add_compile_options(-g -Og --coverage -fstack-protector-all --param=ssp-buffer-size=4)
+    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.13")
+        add_link_options(--coverage)
+    else()
+        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --coverage")
+    endif()
 endif()
 
 option(BUILD_SHARED_LIBS "build shared library" ON)
@@ -51,8 +56,8 @@ if (PISTACHE_BUILD_TESTS)
             APPEND CMAKE_CXX_CPPCHECK
                 "--enable=all"
                 "-DCPPCHECK"
-                "--suppress=*:${PROJECT_SOURCE_DIR}/third-party*"
-                "--suppress=*:${PROJECT_SOURCE_DIR}/tests*"
+                "--suppress=*:${PROJECT_SOURCE_DIR}/third-party/*"
+                "--suppress=*:${PROJECT_SOURCE_DIR}/tests/*"
                 "--suppress=noExplicitConstructor:include/pistache/optional.h"
         )
     else()