diff --git a/coreutils/md5sum.c b/coreutils/md5sum.c
index fad563fe7..a791a41b0 100644
--- a/coreutils/md5sum.c
+++ b/coreutils/md5sum.c
@@ -96,7 +96,7 @@ extern _IO_ssize_t getline __P ((char **, size_t *, FILE *));
 
 #include <stdio.h>
 
-#if defined HAVE_LIMITS_H || _LIBC
+#if defined HAVE_LIMITS_H || defined _LIBC
 # include <limits.h>
 #endif
 
diff --git a/md5sum.c b/md5sum.c
index fad563fe7..a791a41b0 100644
--- a/md5sum.c
+++ b/md5sum.c
@@ -96,7 +96,7 @@ extern _IO_ssize_t getline __P ((char **, size_t *, FILE *));
 
 #include <stdio.h>
 
-#if defined HAVE_LIMITS_H || _LIBC
+#if defined HAVE_LIMITS_H || defined _LIBC
 # include <limits.h>
 #endif
 
diff --git a/networking/telnet.c b/networking/telnet.c
index 3e43c4a1b..40cf7a128 100644
--- a/networking/telnet.c
+++ b/networking/telnet.c
@@ -49,7 +49,7 @@
 #define DOTRACE 1
 #endif
 
-#if DOTRACE
+#ifdef DOTRACE
 #include <arpa/inet.h> /* for inet_ntoa()... */
 #define TRACE(x, y) do { if (x) printf y; } while (0)
 #else
diff --git a/telnet.c b/telnet.c
index 3e43c4a1b..40cf7a128 100644
--- a/telnet.c
+++ b/telnet.c
@@ -49,7 +49,7 @@
 #define DOTRACE 1
 #endif
 
-#if DOTRACE
+#ifdef DOTRACE
 #include <arpa/inet.h> /* for inet_ntoa()... */
 #define TRACE(x, y) do { if (x) printf y; } while (0)
 #else