trying to install ns3gym with ns3.37 on ubuntu 20. Getting error. Kindly help

[PRIYANKA MITTAL]

- Using default output directory /home/vboxuser/Desktop/networksim/ns-allinone-3.37/ns-3.37/build
-- Proceeding without cmake-format
-- find_external_library: SQLite3 was found.
-- Harfbuzz is required by GTK3 and was not found.
-- LibXML2 was found.
-- Visualizer requires Python bindings
-- GSL was found.
-- docs: doxygen documentation not enabled due to missing dependencies: doxygen;dia
-- Failed to locate sphinx-build executable (missing: SPHINX_EXECUTABLE)
-- docs: sphinx documentation not enabled due to missing dependencies: Sphinx;epstopdf;pdflatex;latexmk;convert;dvipng
-- Precompiled headers were enabled
-- Processing contrib/ns3-gym
CMake Error at build-support/custom-modules/ns3-module-macros.cmake:76 (target_precompile_headers):
  Cannot specify precompile headers for target "REUSE_FROM" which is not
  built by this project.
Call Stack (most recent call first):
  contrib/ns3-gym/CMakeLists.txt:40 (build_lib)


CMake Error at build-support/custom-modules/ns3-module-macros.cmake:94 (add_library):
  add_library ALIAS requires exactly one target argument.
Call Stack (most recent call first):
  contrib/ns3-gym/CMakeLists.txt:40 (build_lib)


-- protobuf_generate command not found -> use a local copy from /home/vboxuser/Desktop/networksim/ns-allinone-3.37/ns-3.37/contrib/ns3-gym/protobuf-generate.cmake
CMake Error at build-support/3rd-party/colored-messages.cmake:78 (_message):
  Error: protobuf_generate called without any targets or source
  files
Call Stack (most recent call first):
  contrib/ns3-gym/protobuf-generate.cmake:14 (message)
  contrib/ns3-gym/CMakeLists.txt:62 (protobuf_generate)


CMake Error at build-support/3rd-party/colored-messages.cmake:78 (_message):
  Error: protobuf_generate called without any targets or source
  files
Call Stack (most recent call first):
  contrib/ns3-gym/protobuf-generate.cmake:14 (message)
  contrib/ns3-gym/CMakeLists.txt:69 (protobuf_generate)


-- Processing src/antenna
-- Processing src/aodv
-- Processing src/applications
-- Processing src/bridge
-- Processing src/brite
-- find_external_library: brite was not found. Missing headers: "Brite.h" and missing libraries: "brite".
-- Skipping src/brite
-- Processing src/buildings
-- Processing src/click
-- find_external_library: click was not found. Missing headers: "simclick.h" and missing libraries: "nsclick;click".
-- Skipping src/click
-- Processing src/config-store
-- Processing src/core
-- Boost Units have been found.
-- Processing src/csma
-- Processing src/csma-layout
-- Processing src/dsdv
-- Processing src/dsr
-- Processing src/energy
-- Processing src/fd-net-device
-- Checking for module 'libdpdk'
--   No package 'libdpdk' found
-- Processing src/flow-monitor
-- Processing src/internet
-- Processing src/internet-apps
-- Processing src/lr-wpan
-- Processing src/lte
-- Processing src/mesh
-- Processing src/mobility
-- Processing src/netanim
-- Processing src/network
-- Processing src/nix-vector-routing
-- Processing src/olsr
-- Processing src/openflow
-- find_external_library: openflow was not found. Missing headers: "openflow.h" and missing libraries: "openflow".
-- Skipping src/openflow
-- Processing src/point-to-point
-- Processing src/point-to-point-layout
-- Processing src/propagation
-- Processing src/sixlowpan
-- Processing src/spectrum
-- Processing src/stats
-- Processing src/tap-bridge
-- Processing src/test
-- Processing src/topology-read
-- Processing src/traffic-control
-- Processing src/uan
-- Processing src/virtual-net-device
-- Processing src/wave
-- Processing src/wifi
-- Processing src/wimax
-- ---- Summary of optional ns-3 features:
Build profile                 : default
Build directory               : /home/vboxuser/Desktop/networksim/ns-allinone-3.37/ns-3.37/build
Build version embedding       : OFF (not requested)
BRITE Integration             : OFF (missing dependency)
DES Metrics event collection  : OFF (not requested)
DPDK NetDevice                : OFF (not requested)
Emulation FdNetDevice         : ON
Examples                      : ON
File descriptor NetDevice     : ON
GNU Scientific Library (GSL)  : ON
GtkConfigStore                : OFF (missing dependency)
LibXml2 support               : ON
MPI Support                   : OFF (not requested)
ns-3 Click Integration        : OFF (missing dependency)
ns-3 OpenFlow Integration     : OFF (missing dependency)
Netmap emulation FdNetDevice  : OFF (missing dependency)
PyViz visualizer              : OFF (missing dependency)
Python Bindings               : OFF (not requested)
SQLite support                : ON
Tap Bridge                    : ON
Tap FdNetDevice               : ON
Tests                         : ON


Modules configured to be built:
antenna                   aodv                      applications              
bridge                    buildings                 config-store              
core                      csma                      csma-layout              
dsdv                      dsr                       energy                    
fd-net-device             flow-monitor              internet                  
internet-apps             lr-wpan                   lte                      
mesh                      mobility                  netanim                  
network                   nix-vector-routing        olsr                      
point-to-point            point-to-point-layout     propagation              
sixlowpan                 spectrum                  stats                    
tap-bridge                test                      topology-read            
traffic-control           uan                       virtual-net-device        
wave                      wifi                      wimax                    


Modules that cannot be built:
brite                     click                     mpi                      
ns3-gym                   openflow                  visualizer                



-- Configuring incomplete, errors occurred!
See also "/home/vboxuser/Desktop/networksim/ns-allinone-3.37/ns-3.37/cmake-cache/CMakeFiles/CMakeOutput.log".
See also "/home/vboxuser/Desktop/networksim/ns-allinone-3.37/ns-3.37/cmake-cache/CMakeFiles/CMakeError.log".
Finished executing the following commands:
cd cmake-cache; /usr/bin/cmake -DNS3_EXAMPLES=ON .. ; cd