Fix incorrect handling of positional linker flags

Resolves #1430

Author: valeros

builder/frameworks/espidf.py

@@ -1595,7 +1595,9 @@ def get_python_exe():
 
 # Extra flags which need to be explicitly specified in LINKFLAGS section because SCons
 # cannot merge them correctly
-extra_flags = filter_args(link_args["LINKFLAGS"], ["-T", "-u"])
+extra_flags = filter_args(
+    link_args["LINKFLAGS"], ["-T", "-u", "-Wl,--start-group", "-Wl,--end-group"]
+)
 link_args["LINKFLAGS"] = sorted(list(set(link_args["LINKFLAGS"]) - set(extra_flags)))
 
 # remove the main linker script flags '-T memory.ld'