Fix #3 - use dwarf-3

Not defining strict, which I havent got problem yet in uvision debugger.

Differences for dwarf-4 (we might lose accepting this changeset):
(taken from dwarf4)
• Add support for new C++ language constructs, including rvalue references, generalized
  constant expressions, Unicode character types and template aliases.
• Clarify and generalize support for packed arrays and structures.
• Add new line number table support to facilitate profile based compiler optimization.
• Add additional support for template parameters in instantiations.
• Add support for strongly typed enumerations in languages (such as C++) that have two
  kinds of enumeration declarations.

CMake/Platform/mbedOS-GNU-C.cmake

@@ -11,15 +11,15 @@ set(CMAKE_C_COMPILE_OBJECT        "<CMAKE_C_COMPILER> <DEFINES> <FLAGS> -o <OBJE
 set(CMAKE_C_LINK_EXECUTABLE       "<CMAKE_C_COMPILER> <CMAKE_C_LINK_FLAGS> <LINK_FLAGS> -Wl,-Map,<TARGET>.map -Wl,--start-group <OBJECTS> <LINK_LIBRARIES> ${GLOBALLY_LINKED_TARGET_LIBS} -lm -lc -lgcc -lm -lc -lgcc -Wl,--end-group  --specs=nano.specs -o <TARGET>")
 
 
-set(CMAKE_C_FLAGS_DEBUG_INIT          "-g")
+set(CMAKE_C_FLAGS_DEBUG_INIT          "-g -gdwarf-3")
 set(CMAKE_C_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_C_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-Os -g -DNDEBUG")
+set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-3 -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
 
 
-set(CMAKE_ASM_FLAGS_DEBUG_INIT          "-g")
+set(CMAKE_ASM_FLAGS_DEBUG_INIT          "-g -gdwarf-3")
 set(CMAKE_ASM_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_ASM_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_ASM_FLAGS_RELWITHDEBINFO_INIT "-Os -g -DNDEBUG")
+set(CMAKE_ASM_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-3 -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_ASM  "-isystem ")

CMake/Platform/mbedOS-GNU-CXX.cmake

@@ -20,8 +20,8 @@ set(CMAKE_CXX_COMPILE_OBJECT        "<CMAKE_CXX_COMPILER> <DEFINES> <FLAGS> -o <
 # functions (e.g. malloc) can be overridden by symbols in <LINK_LIBRARIES>
 set(CMAKE_CXX_LINK_EXECUTABLE       "<CMAKE_CXX_COMPILER> <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> -Wl,-Map,<TARGET>.map -Wl,--start-group <OBJECTS> <LINK_LIBRARIES> ${GLOBALLY_LINKED_TARGET_LIBS} -lstdc++ -lsupc++ -lm -lc -lgcc -lstdc++ -lsupc++ -lm -lc -lgcc -Wl,--end-group  --specs=nano.specs -o <TARGET>")
 
-set(CMAKE_CXX_FLAGS_DEBUG_INIT          "-g")
+set(CMAKE_CXX_FLAGS_DEBUG_INIT          "-g -gdwarf-3")
 set(CMAKE_CXX_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_CXX_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-Os -g -DNDEBUG")
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-3 -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-isystem ")