--- rstudio-1.3.959-orig/src/cpp/desktop/CMakeLists.txt	2020-05-19 04:11:10.000000000 +1000
+++ rstudio-1.3.959/src/cpp/desktop/CMakeLists.txt	2020-05-24 17:15:47.039422975 +1000
@@ -138,6 +138,13 @@
 get_filename_component(QT_LIBRARY_PATH "${QT_BIN_DIR}/../lib"     ABSOLUTE CACHE)
 get_filename_component(QT_INSTALL_PATH "${QT_BIN_DIR}/.."         ABSOLUTE CACHE)
 
+find_path(QTSINGLEAPPLIB_INCLUDE_DIR NAMES QtSingleApplication
+  PATH_SUFFIXES QtSolutions
+  PATHS
+  /usr/include/qt5)
+find_library(QTSINGLEAPPLIB Qt5Solutions_SingleApplication-2.6
+  libQt5Solutions_SingleApplication-2.6)
+
 # disable clang warnings for qt sources
 if(APPLE)
    add_definitions(-Wno-unused-private-field
@@ -156,7 +163,6 @@
 
 set(MOC_DESKTOP_HEADER_FILES ${DESKTOP_HEADER_FILES})
 list(REMOVE_ITEM MOC_DESKTOP_HEADER_FILES
-  ${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/qtsingleapplication/qtlockedfile.h
   ${CMAKE_CURRENT_SOURCE_DIR}/DesktopDetectRHome.hpp
   ${CMAKE_CURRENT_SOURCE_DIR}/DesktopOptions.hpp
   ${CMAKE_CURRENT_SOURCE_DIR}/DesktopRVersion.hpp
@@ -225,8 +231,6 @@
   DesktopSynctex.cpp
   DesktopJobLauncherOverlay.cpp
   RemoteDesktopSessionLauncherOverlay.cpp
-  3rdparty/qtsingleapplication/qtsingleapplication.cpp
-  3rdparty/qtsingleapplication/qtlocalpeer.cpp
 )
 
 if(WIN32)
@@ -283,6 +287,7 @@
   ${OPENSSL_INCLUDE_DIR}
   ${CMAKE_CURRENT_SOURCE_DIR}
   ${CMAKE_CURRENT_BINARY_DIR}
+  ${QTSINGLEAPPLIB_INCLUDE_DIR}
   ${EXT_SOURCE_DIR}
   ${SESSION_SOURCE_DIR}/include
   ${TESTS_INCLUDE_DIR}
@@ -386,6 +391,7 @@
    # set link dependencies
    target_link_libraries(rstudio
       ${RSTUDIO_QTMODULES}
+      ${QTSINGLEAPPLIB}
       ${QT_LIBRARIES}
       ${Boost_LIBRARIES}
       rstudio-core
--- rstudio-1.3.959-orig/src/cpp/desktop/DesktopPosixApplication.hpp	2020-05-19 04:11:10.000000000 +1000
+++ rstudio-1.3.959/src/cpp/desktop/DesktopPosixApplication.hpp	2020-05-24 17:13:22.050016953 +1000
@@ -16,7 +16,7 @@
 #ifndef DESKTOP_POSIX_APPLICATION_HPP
 #define DESKTOP_POSIX_APPLICATION_HPP
 
-#include "3rdparty/qtsingleapplication/QtSingleApplication"
+#include <QtSingleApplication>
 
 #include "DesktopApplicationLaunch.hpp"