Fix compilation on 2.4.20 kernel based system

* block.c (block_ioctl): add ifdef/endif around BLKGETSIZE64 usage
* strace.c (trace): add ifdef/endif around WIFCONTINUED usage

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/strace.c b/strace.c
index 7314d4a..df10a72 100644
--- a/strace.c
+++ b/strace.c
@@ -2450,8 +2450,10 @@
 				sprintf(buf, "WIFEXITED,exitcode=%u", WEXITSTATUS(status));
 			if (WIFSTOPPED(status))
 				sprintf(buf, "WIFSTOPPED,sig=%s", signame(WSTOPSIG(status)));
+#ifdef WIFCONTINUED
 			if (WIFCONTINUED(status))
 				strcpy(buf, "WIFCONTINUED");
+#endif
 			fprintf(stderr, " [wait(0x%04x) = %u] %s\n", status, pid, buf);
 		}