File rnp-v0.17.0-system-sexp.patch of Package rnp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0fa5aa14c..d64927540 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,6 +58,8 @@ option(ENABLE_COVERAGE "Enable code coverage testing.")
 option(ENABLE_SANITIZERS "Enable ASan and other sanitizers.")
 option(ENABLE_FUZZERS "Enable fuzz targets.")
 option(DOWNLOAD_GTEST "Download Googletest" On)
+option(SYSTEM_LIBSEXPP "Use system sexpp library" OFF)
+
 # crypto components
 function(tristate_feature_auto NAME DESCRIPTION)
   set(${NAME} Auto CACHE STRING ${DESCRIPTION})
@@ -182,10 +184,22 @@ if (ENABLE_FUZZERS)
 endif()
 add_subdirectory(src/common)
 
-set(WITH_SEXP_CLI OFF)
-set(WITH_SEXP_TESTS OFF)
-set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME development)
-add_subdirectory(src/libsexp EXCLUDE_FROM_ALL)
+if (SYSTEM_LIBSEXPP)
+  find_package(PkgConfig)
+  pkg_check_modules(REQUIRED sexpp>=0.8.7)
+else (SYSTEM_LIBSEXPP)
+# If we use system libsexpp is not used we build sexpp static library
+# If librnp is shared, libsexpp.a is a transient artifact which is hidden from
+# the end user. 
+# If librnp is static we install libsexpp.a aside
+  set(SAVED_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS})
+  set(BUILD_SHARED_LIBS OFF)
+  set(WITH_SEXP_CLI OFF)
+  set(WITH_SEXP_TESTS OFF)
+  set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME development)
+  add_subdirectory(src/libsexpp EXCLUDE_FROM_ALL)
+  set(BUILD_SHARED_LIBS ${SAVED_BUILD_SHARED_LIBS})
+endif (SYSTEM_LIBSEXPP)
 
 add_subdirectory(src/lib)
 add_subdirectory(src/rnp)
diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index d931701a5..19059c2fa 100755
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -342,7 +342,7 @@ elseif (CRYPTO_BACKEND_OPENSSL)
   target_link_libraries(librnp-obj PRIVATE OpenSSL::Crypto)
 endif()
 
-target_link_libraries(librnp-obj PRIVATE sexp)
+target_link_libraries(librnp-obj PRIVATE sexpp)
 
 set_target_properties(librnp-obj PROPERTIES CXX_VISIBILITY_PRESET hidden)
 if (TARGET BZip2::BZip2)
@@ -398,7 +398,7 @@ foreach (prop LINK_LIBRARIES INTERFACE_LINK_LIBRARIES INCLUDE_DIRECTORIES INTERF
   get_target_property(val librnp-obj ${prop})
   if (BUILD_SHARED_LIBS)
     set_property(TARGET librnp-static PROPERTY ${prop} ${val})
-    list(REMOVE_ITEM val "$<LINK_ONLY:sexp>")
+    list(REMOVE_ITEM val "$<LINK_ONLY:sexpp>")
     set_property(TARGET librnp PROPERTY ${prop} ${val})
   else()
     set_property(TARGET librnp PROPERTY ${prop} ${val})
@@ -431,12 +431,11 @@ endif()
 # On Unix like systems we will build/install/pack either shared library librnp.so or static  librnp.a
 # On Windows we will build/install/pack either dynamic and import libraries rnp.dll, rnp.lib or static library rnp-static.lib
 
-# If a client application uses shared rnp library, sexp is statically linked to librnp.so and libsexp.a is not installed
-# If a client application uses static rnp library, it still needs libsexp.a and it is installed
+# If a client application uses shared rnp library, sexpp is statically linked to librnp.so and libsexpp.a is not installed
+# If a client application uses static rnp library, it still needs libsexpp.a and it is installed
 
 if (BUILD_SHARED_LIBS)
-# both static and shared libraries
-install(TARGETS librnp
+  install(TARGETS librnp
     EXPORT rnp-targets
     LIBRARY
       DESTINATION  "${CMAKE_INSTALL_LIBDIR}"
@@ -456,13 +455,23 @@ install(TARGETS librnp
     )
   endif(WIN32)
 else(BUILD_SHARED_LIBS)
-# static libraries only
-  install(TARGETS librnp sexp
+# static libraries
+# install libsexpp unless system-installed libsexpp is used
+  if (SYSTEM_LIBSEXPP)
+    install(TARGETS librnp
+      EXPORT rnp-targets
+      ARCHIVE
+        DESTINATION  "${CMAKE_INSTALL_LIBDIR}"
+        COMPONENT development
+    )
+  else (SYSTEM_LIBSEXPP)       
+    install(TARGETS librnp sexpp
     EXPORT rnp-targets
     ARCHIVE
       DESTINATION  "${CMAKE_INSTALL_LIBDIR}"
       COMPONENT development
-)
+    )
+  endif (SYSTEM_LIBSEXPP)       
 endif(BUILD_SHARED_LIBS)
 
 # install headers
diff --git a/src/librekey/g23_sexp.hpp b/src/librekey/g23_sexp.hpp
index b888680f5..b062c52f1 100644
--- a/src/librekey/g23_sexp.hpp
+++ b/src/librekey/g23_sexp.hpp
@@ -27,8 +27,8 @@
 #ifndef RNP_G23_SEXP_HPP
 #define RNP_G23_SEXP_HPP
 
-#include "sexp/sexp.h"
-#include "sexp/ext-key-format.h"
+#include "sexpp/sexp.h"
+#include "sexpp/ext-key-format.h"
 
 #define SXP_MAX_DEPTH 30
 
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -186,7 +186,7 @@ target_link_libraries(rnp_tests
   PRIVATE
     librnp-static
     JSON-C::JSON-C
-    sexp
+    sexpp
     ${GTestMain}
 )
 if (CRYPTO_BACKEND_LOWERCASE STREQUAL "openssl")