build: drop -Wdangling-reference GCC suppression

Author: kwvg

configure.ac

@@ -450,21 +450,14 @@ if test "$enable_werror" = "yes"; then
   fi
   ERROR_CXXFLAGS=$CXXFLAG_WERROR
 
-  dnl -Warray-bounds and -Wdangling-reference cause problems with GCC. Do not treat these warnings as errors.
+  dnl -Warray-bounds cause problems with GCC. Do not treat these warnings as errors.
   dnl Suppress -Warray-bounds entirely because of noisy output, currently unhappy with immer implementation.
   AX_CHECK_COMPILE_FLAG([-Warray-bounds], [NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-array-bounds"], [], [$CXXFLAG_WERROR], [AC_LANG_SOURCE([
     #if defined(__clang__) || defined(__INTEL_COMPILER) || !defined(__GNUC__)
       #error Non-GCC compiler detected, not setting flag
     #endif
     int main(void) { return 0; }
   ])])
-  dnl TODO: Remove suppression after backporting bitcoin#27605
-  AX_CHECK_COMPILE_FLAG([-Wdangling-reference], [NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-error=dangling-reference"], [], [$CXXFLAG_WERROR], [AC_LANG_SOURCE([
-    #if defined(__clang__) || defined(__INTEL_COMPILER) || !defined(__GNUC__)
-      #error Non-GCC compiler detected, not setting flag
-    #endif
-    int main(void) { return 0; }
-  ])])
 
   dnl -Wattributes cause problems with some versions of GCC. Do not treat these warnings as errors.
   AX_CHECK_COMPILE_FLAG([-Wattributes], [NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-error=attributes"], [], [$CXXFLAG_WERROR], [AC_LANG_SOURCE([