libbpf: Fix build by renaming variables

In btf__align_of() variable name 't' is shadowed by inner block
declaration of another variable with same name. Patch renames
variables in order to fix it.

  CC       sharedobjs/btf.o
btf.c: In function ‘btf__align_of’:
btf.c:303:21: error: declaration of ‘t’ shadows a previous local [-Werror=shadow]
  303 |   int i, align = 1, t;
      |                     ^
btf.c:283:25: note: shadowed declaration is here
  283 |  const struct btf_type *t = btf__type_by_id(btf, id);
      |

Fixes: 3d208f4c ("libbpf: Expose btf__align_of() API")
Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20191216082738.28421-1-prashantbhole.linux@gmail.com

tools/lib/bpf/btf.c

@@ -300,16 +300,16 @@ int btf__align_of(const struct btf *btf, __u32 id)
 	case BTF_KIND_UNION: {
 		const struct btf_member *m = btf_members(t);
 		__u16 vlen = btf_vlen(t);
-		int i, align = 1, t;
+		int i, max_align = 1, align;
 
 		for (i = 0; i < vlen; i++, m++) {
-			t = btf__align_of(btf, m->type);
-			if (t <= 0)
-				return t;
-			align = max(align, t);
+			align = btf__align_of(btf, m->type);
+			if (align <= 0)
+				return align;
+			max_align = max(max_align, align);
 		}
 
-		return align;
+		return max_align;
 	}
 	default:
 		pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t));