fix build issues when building stm32f4discovery with elf and cpp exceptions

[abhishek-samsung]

Summary

binfmt/libelf: add exidx and extab sections in linker script

exidx and extab sections are required for exception handling, hence
add them to the elf linker script

include/nuttx: fix "unknown type name bool" build error in elf.h

fix the following error by including stdbool.h in elf.h

CC:  machine/arm/gnu_unwind_find_exidx.c In file included from machine/arm/gnu_unwind_find_exidx.c:25:
/home/abhishek/Work/public/nuttx_build/nuttx/include/nuttx/elf.h:118:1: error: unknown type name 'bool'
  118 | bool up_checkarch(FAR const Elf_Ehdr *hdr);
      | ^~~~
make[1]: *** [Makefile:153: bin/gnu_unwind_find_exidx.o] Error 1
make: *** [tools/LibTargets.mk:180: libs/libc/libc.a] Error 2

Impact

Testing