fix deprecated glslang include in cmake

src/CMakeLists.txt

@@ -98,28 +98,12 @@ else()
 endif()
 
 if(USE_SYSTEM_NCNN)
-    set(GLSLANG_TARGET_DIR "GLSLANG-NOTFOUND" CACHE PATH "Absolute path to glslangTargets.cmake directory")
-    if(NOT GLSLANG_TARGET_DIR AND NOT DEFINED ENV{GLSLANG_TARGET_DIR})
-        message(WARNING "GLSLANG_TARGET_DIR must be defined! USE_SYSTEM_NCNN will be turned off.")
+    find_package(glslang)
+    add_library(SPIRV ALIAS glslang::SPIRV)
+    add_library(glslang ALIAS glslang::glslang)
+    if (NOT TARGET glslang or NOT TARGET SPIRV)
+        message(WARNING "glslang or SPIRV target not found! USE_SYSTEM_NCNN will be turned off.")
         set(USE_SYSTEM_NCNN OFF)
-    else()
-        message(STATUS "Using glslang install located at ${GLSLANG_TARGET_DIR}")
-
-        find_package(Threads)
-
-        include("${GLSLANG_TARGET_DIR}/OSDependentTargets.cmake")
-        include("${GLSLANG_TARGET_DIR}/OGLCompilerTargets.cmake")
-        if(EXISTS "${GLSLANG_TARGET_DIR}/HLSLTargets.cmake")
-            # hlsl support can be optional
-            include("${GLSLANG_TARGET_DIR}/HLSLTargets.cmake")
-        endif()
-        include("${GLSLANG_TARGET_DIR}/glslangTargets.cmake")
-        include("${GLSLANG_TARGET_DIR}/SPIRVTargets.cmake")
-
-        if (NOT TARGET glslang OR NOT TARGET SPIRV)
-            message(WARNING "glslang or SPIRV target not found! USE_SYSTEM_NCNN will be turned off.")
-            set(USE_SYSTEM_NCNN OFF)
-        endif()
     endif()
 endif()