pkg-config overrides for RHEL 7 and CentOS 7
RHEL 7 and CentOS 7 do not provide pkg-config .pc files for Tcl/Tk. The OpenSSL 1.1.1 pkg-config file is named openssl11.pc and not picked up by Python's configure script.
To build Python with system Tcl/Tk libs and OpenSSL 1.1 package, first install the developer packages and the pkgconfig package with pkg-config command.
The run configure with PKG_CONFIG_PATH environment variable.