Append SDE pkgconfig folders to PKG_CONFIG_PATH (#319)

- Check for `pkgconfig` directories in the DPDK SDE and append them to
  PKG_CONFIG_PATH before using pkg-config to find the DPDK module.

- Address a CMake module warning by using `DpdkDriver` as the DPDK
  package name instead of `DPDK`.

- Correct an error in a DPDK LDFLAGS variable reference.

- Update krnlmon submodule reference.

Signed-off-by: Derek G Foster <[email protected]>

cmake/FindDpdkDriver.cmake

@@ -7,12 +7,6 @@
 # This module requires that SDE_INSTALL_DIR be defined.
 # It needs additional work to make it a proper CMake find-module.
 
-#-----------------------------------------------------------------------
-# Use pkg-config to find DPDK module
-#-----------------------------------------------------------------------
-include(FindPkgConfig)
-pkg_check_modules(DPDK REQUIRED libdpdk)
-
 #-----------------------------------------------------------------------
 # Define SDE_INCLUDE_DIR
 #-----------------------------------------------------------------------
@@ -121,12 +115,40 @@ set_target_properties(sde::target_utils PROPERTIES
     INTERFACE_INCLUDE_DIRECTORIES ${SDE_INCLUDE_DIR}
     IMPORTED_LINK_INTERFACE_LANGUAGES C)
 
+#-----------------------------------------------------------------------
+# Append SDE pkgconfig directories to PKG_CONFIG_PATH
+#-----------------------------------------------------------------------
+function(_set_pkg_config_path)
+  file(TO_CMAKE_PATH "$ENV{PKG_CONFIG_PATH}" _sde_pkg_path)
+
+  foreach(_libdir lib lib64 lib/x86_64-linux-gnu)
+    set(_path ${SDE_INSTALL_DIR}/${_libdir}/pkgconfig)
+    if(EXISTS ${_path})
+      list(APPEND _sde_pkg_path ${_path})
+    endif()
+  endforeach()
+
+  list(JOIN _sde_pkg_path ":" _sde_pkg_path)
+
+  if(NOT _sde_pkg_path STREQUAL "")
+    set(ENV{PKG_CONFIG_PATH} "${_sde_pkg_path}")
+  endif()
+endfunction()
+
+_set_pkg_config_path()
+
+#-----------------------------------------------------------------------
+# Use pkg-config to find DPDK module
+#-----------------------------------------------------------------------
+include(FindPkgConfig)
+pkg_check_modules(DpdkDriver REQUIRED libdpdk)
+
 #-----------------------------------------------------------------------
 # Define SDE_LIBRARY_DIRS
 #-----------------------------------------------------------------------
 set(SDE_LIBRARY_DIRS
     ${SDE_INSTALL_DIR}/lib
-    ${DPDK_LIBRARY_DIRS}
+    ${DpdkDriver_LIBRARY_DIRS}
 )
 
 #-----------------------------------------------------------------------
@@ -145,7 +167,7 @@ function(add_dpdk_target_libraries TGT)
   target_link_directories(${TGT} PUBLIC ${SDE_LIBRARY_DIRS})
 
   target_link_options(${TGT} PUBLIC
-      ${DPDK_LD_FLAGS}
-      ${DPDK_LDFLAGS_OTHER}
+      ${DpdkDriver_LDFLAGS}
+      ${DpdkDriver_LDFLAGS_OTHER}
   )
 endfunction()