diff --git a/kcontrol/tdefontinst/tdefontinst/GetPid.c b/kcontrol/tdefontinst/tdefontinst/GetPid.c
index 37aba65c3..1a633a76b 100644
--- a/kcontrol/tdefontinst/tdefontinst/GetPid.c
+++ b/kcontrol/tdefontinst/tdefontinst/GetPid.c
@@ -83,7 +83,7 @@
     6. Email me and let me know if it works!
 */
 
-#if defined OS_Linux || defined __Linux__
+#if defined OS_Linux || defined __linux__
 
 #include <dirent.h>
 #include <ctype.h>
diff --git a/kdesktop/lock/lockprocess.cc b/kdesktop/lock/lockprocess.cc
index ff820f0f4..1de0b6753 100644
--- a/kdesktop/lock/lockprocess.cc
+++ b/kdesktop/lock/lockprocess.cc
@@ -79,7 +79,7 @@
 
 #include <kcrash.h>
 
-#ifdef __Linux__
+#ifdef __linux__
 #include <linux/stat.h>
 #endif
 
diff --git a/tdm/backend/ctrl.c b/tdm/backend/ctrl.c
index 9fc3f6b12..4acd6d293 100644
--- a/tdm/backend/ctrl.c
+++ b/tdm/backend/ctrl.c
@@ -42,7 +42,7 @@ from the copyright holder.
 #include <signal.h>
 #include <pwd.h>
 
-#ifdef __Linux__
+#ifdef __linux__
 #include <linux/vt.h>
 #endif
 #include "getfd.h"
diff --git a/tdm/backend/getfd.c b/tdm/backend/getfd.c
index 07973e642..6bf8c8783 100644
--- a/tdm/backend/getfd.c
+++ b/tdm/backend/getfd.c
@@ -4,7 +4,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/ioctl.h>
-#ifdef __Linux__
+#ifdef __linux__
 #include <linux/kd.h>
 #endif
 #include "getfd.h"