[nfc] simplify llvm version check

Use standard cmake version check functionality rather than hand crafted
regex matching. It's more compact and less bug prone

Author: ferdymercury

interpreter/CMakeLists.txt

@@ -275,7 +275,7 @@ if(builtin_llvm)
     set(LLVM_TABLEGEN_EXE "${LLVM_BINARY_DIR}/bin/llvm-tblgen")
   endif()
 else()
-  find_package(LLVM REQUIRED CONFIG)
+  find_package(LLVM ${ROOT_LLVM_VERSION_REQUIRED_MAJOR}.1 REQUIRED CONFIG)
   message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION} in ${LLVM_CMAKE_DIR}")
 
   separate_arguments(LLVM_DEFINITIONS_LIST NATIVE_COMMAND ${LLVM_DEFINITIONS})
@@ -320,13 +320,6 @@ else()
   include(HandleLLVMOptions)
   include(VersionFromVCS)
 
-  set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
-  if (${PACKAGE_VERSION} MATCHES "${ROOT_LLVM_VERSION_REQUIRED_MAJOR}\\.1(|\\.[0-9]+)")
-    message(STATUS "Using LLVM external library - ${PACKAGE_VERSION}")
-  else()
-    message(FATAL_ERROR "LLVM version ${LLVM_PACKAGE_VERSION} different from ROOT supported, please try ${ROOT_LLVM_VERSION_REQUIRED_MAJOR}.1.x")
-  endif()
-
   if (NOT DEFINED LLVM_INCLUDE_TESTS)
     set(LLVM_INCLUDE_TESTS ON)
   endif()