Expose IE_THREAD definition to end users (#14476)

cmake/templates/openvino.pc.in

@@ -17,6 +17,6 @@ Description: OpenVINO™ Toolkit
 URL: https://docs.openvino.ai/latest/index.html
 Version: @OpenVINO_VERSION@
 Conflicts: openvino < @OpenVINO_VERSION@
-Cflags: -I${includedir_old} -I${includedir_new}
+Cflags: -I${includedir_old} -I${includedir_new} @PKGCONFIG_OpenVINO_DEFINITIONS@
 Libs: -L${libdir} @PKGCONFIG_OpenVINO_FRONTENDS@ -lopenvino_c -lopenvino @PKGCONFIG_OpenVINO_PRIVATE_DEPS@
 Libs.private: -ldl -lm -lpthread -lrt

src/cmake/ie_parallel.cmake

@@ -300,7 +300,7 @@ function(set_ie_threading_interface_for TARGET_NAME)
         endif ()
     endif ()
 
-    target_compile_definitions(${TARGET_NAME} ${LINK_TYPE} -DIE_THREAD=${IE_THREAD_DEFINE})
+    target_compile_definitions(${TARGET_NAME} ${COMPILE_DEF_TYPE} -DIE_THREAD=${IE_THREAD_DEFINE})
 
     if (NOT THREADING STREQUAL "SEQ")
         find_package(Threads REQUIRED)

src/cmake/openvino.cmake

@@ -195,6 +195,12 @@ install(FILES "${CMAKE_BINARY_DIR}/share/OpenVINOConfig.cmake"
 # Generate and install openvino.pc pkg-config file
 
 if(ENABLE_PKGCONFIG_GEN)
+    # fill in PKGCONFIG_OpenVINO_DEFINITIONS
+    get_target_property(openvino_defs openvino INTERFACE_COMPILE_DEFINITIONS)
+    foreach(openvino_def IN LISTS openvino_defs)
+        set(PKGCONFIG_OpenVINO_DEFINITIONS "${PKGCONFIG_OpenVINO_DEFINITIONS} -D${openvino_def}")
+    endforeach()
+
     # fill in PKGCONFIG_OpenVINO_FRONTENDS
     get_target_property(PKGCONFIG_OpenVINO_FRONTENDS_LIST ov_frontends MANUALLY_ADDED_DEPENDENCIES)
     if(ENABLE_OV_IR_FRONTEND)