cmake: pass -fdebug-prefix-map so that debug entries contain relative source locations

Author: rsomla1

cdk/cmake/compiler/GCC.cmake

@@ -28,6 +28,18 @@
 
 ##########################################################################
 
+#
+# Ensure relative source locations in debug entries
+#
+
+foreach(LANG C CXX)
+foreach(TYPE DEBUG RELWITHDEBINFO)
+  set(CMAKE_${LANG}_FLAGS_${TYPE}
+    "-fdebug-prefix-map=${CMAKE_SOURCE_DIR}=. ${CMAKE_${LANG}_FLAGS_${TYPE}}"
+  )
+endforeach(TYPE)
+endforeach(LANG)
+
 #
 # Deal with broken optimization in gcc 4.8.
 #