Add LTO support check if genai is built without openvino dev package (openvinotoolkit#3712)

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## Description
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motivation and context. -->

Add LTO support check if genai is built without openvino dev package. If
OpenVINODeveloperPackage_FOUND, such check is performed in
OpenVINODeveloperScriptsConfig.cmake

## Checklist:
- [x] This PR follows [GenAI Contributing
guidelines](https://github.com/openvinotoolkit/openvino.genai?tab=contributing-ov-file#contributing).
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- [x] This PR fully addresses the ticket. <!--- If not, explain clearly
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Author: olpipi

cmake/features.cmake

@@ -10,6 +10,18 @@ option(ENABLE_TESTS "Enable tests build" ON)
 option(ENABLE_TOOLS "Enable tools build" ON)
 option(ENABLE_GGUF "Enable support for GGUF format" ON)
 option(ENABLE_XGRAMMAR "Enable support for structured output generation with xgrammar backend" ON)
+option(ENABLE_LTO "Enable Link Time Optimization" OFF)
+
+# When building without OpenVINODeveloperPackage, verify IPO/LTO support
+if(ENABLE_LTO AND NOT OpenVINODeveloperPackage_FOUND)
+    include(CheckIPOSupported)
+    check_ipo_supported(RESULT IPO_SUPPORTED
+                        OUTPUT OUTPUT_MESSAGE
+                        LANGUAGES C CXX)
+    if(NOT IPO_SUPPORTED)
+        message(FATAL_ERROR "ENABLE_LTO is ON but IPO / LTO is not supported: ${OUTPUT_MESSAGE}")
+    endif()
+endif()
 
 # Disable building samples for NPM package
 if(CPACK_GENERATOR STREQUAL "NPM")

src/CMakeLists.txt

@@ -61,10 +61,6 @@ else()
     set(RUNTIME_DESTINATION runtime/bin/${ARCH_DIR})
 endif()
 
-if(NOT DEFINED ENABLE_LTO)
-    set(ENABLE_LTO OFF)
-endif()
-
 #
 # Include source dirs
 #