Xtensa-esp32-elf-gdb should not depend on obsolete libpython2.7.so.1.0

[maxgerhardt]

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Problem with esp32 debug for Ubuntu. (undefined symbol: _Py_ZeroStruct)

Indeed Ubuntu 20 support seems to lacking / hacky right now. I installed a fresh Ubuntu 20.04 LTS in a VM. Even got an install error in VSCode which was solvable though. The problem with the xtensa-esp32-elf-gdb is however reproducable: max@max-VirtualBox:~/.platformio/packages/toolchain-xtensa32/bin$ ldd xtensa-esp32-elf-gdb linux-vdso.so.1 (0x00007ffdc2af0000) libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fed2a94f000) libncurses.so.5 => not found libtinfo.so.5 => not found libm…