fix os variable reference

Author: martin-frbg

cmake/system.cmake

@@ -367,13 +367,13 @@ if (${TARGET} STREQUAL NEOVERSEV1)
   endif()
   if (${TARGET} STREQUAL ARMV9SME)
       set (KERNEL_DEFINITIONS  "${KERNEL_DEFINITIONS} -march=armv9-a+sme -O3")
-	  if (${OSNAME} STREQUAL WINDOWS AND ${CMAKE_C_COMPILER_ID} MATCHES "Clang")
+	  if (${CMAKE_SYSTEM_NAME} STREQUAL Windows AND ${CMAKE_C_COMPILER_ID} MATCHES "Clang")
 	  set (KERNEL_DEFINITIONS  "${KERNEL_DEFINITIONS} --aarch64-stack-hazard-size=0")
 	  endif()
   endif()
   if (${TARGET} STREQUAL VORTEXM4)
       set (KERNEL_DEFINITIONS  "${KERNEL_DEFINITIONS} -march=armv8.4-a+sme -O3")
-	  if (${OSNAME} STREQUAL WINDOWS AND ${CMAKE_C_COMPILER_ID} MATCHES "Clang")
+	  if (${CMAKE_SYSTEM_NAME} STREQUAL Windows AND ${CMAKE_C_COMPILER_ID} MATCHES "Clang")
 	  set (KERNEL_DEFINITIONS  "${KERNEL_DEFINITIONS} --aarch64-stack-hazard-size=0")
 	  endif()
   endif()