Java Development Kit (JDK) directory is not set or invalid. Please, fix it in Preferences -> External Tools UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) code example

Example 1: Could not build the ssl module! Python requires an OpenSSL 1.0.2 or 1.1 compatible libssl with X509_VERIFY_PARAM_set1_host(). LibreSSL 2.6.4 and earlier do not provide the necessary APIs, https://github.com/libressl-portable/portable/issues/381

$ cd ~
$ wget https://www.openssl.org/source/openssl-1.1.1b.tar.gz
$ wget https://www.openssl.org/source/openssl-1.1.1b.tar.gz.sha256
$ sha256sum openssl-1.1.1b.tar.gz
$ cat openssl-1.1.1b.tar.gz.sha256
$ tar zxvf openssl-1.1.1b.tar.gz
$ ls /home/username/
$ ./config --prefix=/home/username/openssl --openssldir=/home/username/openssl no-ssl2
$ cd openssl-1.1.1b
$ ./config --prefix=/home/username/openssl --openssldir=/home/username/openssl no-ssl2
$ make
$ make test
$ make install
$ cd ~
$ vim ./.bash_profile
$ source .bash_profile
$ which openssl
$ openssl version
$ cd Python-3.7.6
$ ./configure --prefix=$HOME/.local --with-ensurepip=yes CFLAGS="-I$HOME/openssl/include" LDFLAGS="-L$HOME/openssl/lib"
$ make
$ make install
$ source ~/.bash_profile
$ python3 -V

Example 2: protoc-gen-go: program not found or is not executable Please specify a program using absolute path or make sure the program is available in your PATH system variable --go_out: protoc-gen-go: Plugin failed with status code 1.

export GOROOT=/usr/local/go
export GOPATH=$HOME/go
export GOBIN=$GOPATH/bin
export PATH=$PATH:$GOROOT:$GOPATH:$GOBIN