fix miss header

[Silverlan]

This fixes the following build error with gcc-15:

FAILED: [code=1] build/linux-x64/release/obj/frida/backtracer.obj 
gcc -MMD -MT build/linux-x64/release/obj/frida/backtracer.obj -MF build/linux-x64/release/obj/frida/backtracer.obj.d -std=c++17 -O2 -Wall -fvisibility=hidden -I3rd/frida_gum/linux-x86_64 -I3rd/frida_gum/gumpp -DGUMPP_STATIC -DNDEBUG -fPIC -o build/linux-x64/release/obj/frida/backtracer.obj -c 3rd/frida_gum/gumpp/src/backtracer.cpp
In file included from 3rd/frida_gum/gumpp/src/backtracer.cpp:1:
3rd/frida_gum/gumpp/gumpp.hpp:247:17: error: ‘uint32_t’ does not name a type
  247 |         virtual uint32_t line_number() const = 0;
      |                 ^~~~~~~~