Alter linux debug stacktraces handling to support more environments

- Use -gdwarf-4 to support both LLVM and GCC when calling addr2line
- Subtract position-independant execuable relocation when passing the
  address to addr2line

(cherry picked from commit 5e041eee11)

platform/server/detect.py

@@ -51,7 +51,6 @@ def get_flags():
 
 
 def configure(env):
-
     ## Build type
 
     if env["target"] == "release":
@@ -76,6 +75,11 @@ def configure(env):
         env.Prepend(CCFLAGS=["-g3"])
         env.Append(LINKFLAGS=["-rdynamic"])
 
+    if env["debug_symbols"]:
+        # Adding dwarf-4 explicitly makes stacktraces work with clang builds,
+        # otherwise addr2line doesn't understand them
+        env.Append(CCFLAGS=["-gdwarf-4"])
+
     ## Architecture
 
     is64 = sys.maxsize > 2**32