rustc_trans: don't hardcode llvm version for conditional intrinsics

This commit introduce a third parameter for compatible_ifn!, as new
intrinsics are being added in recent LLVM releases and there is no
need to hardcode a specific case.

Signed-off-by: Luca Bruno <lucab@debian.org>

src/rustllvm/RustWrapper.cpp

@@ -237,6 +237,14 @@ extern "C" uint32_t LLVMRustDebugMetadataVersion() {
     return DEBUG_METADATA_VERSION;
 }
 
+extern "C" uint32_t LLVMVersionMinor() {
+  return LLVM_VERSION_MINOR;
+}
+
+extern "C" uint32_t LLVMVersionMajor() {
+  return LLVM_VERSION_MAJOR;
+}
+
 extern "C" void LLVMRustAddModuleFlag(LLVMModuleRef M,
                                       const char *name,
                                       uint32_t value) {