Use '.L' as labelprefix for LLVM compiler variant

compiler/llvm/agllvm.pas

@@ -1755,7 +1755,7 @@ implementation
           asmcmd: '-x ir $OPT -target $TRIPLET -c -o $OBJ $ASM $EXTRAOPT';
           supported_targets : [system_x86_64_linux,system_x86_64_darwin,system_aarch64_darwin,system_aarch64_linux,system_arm_linux];
           flags : [af_smartlink_sections,af_llvm];
-          labelprefix : 'L';
+          labelprefix : '.L';
           labelmaxlen : -1;
           comment : '; ';
           dollarsign: '$';