diff --git a/components/battery.c b/components/battery.c
index 4314e81..aef5b5f 100644
--- a/components/battery.c
+++ b/components/battery.c
@@ -1,10 +1,10 @@
 /* See LICENSE file for copyright and license details. */
 #include <err.h>
 #include <stdio.h>
-#ifdef __linux__
+#if defined(__linux__)
 #include <limits.h>
 #include <string.h>
-#elif __OpenBSD__
+#elif defined(__OpenBSD__)
 #include <sys/ioctl.h>
 #include <fcntl.h>
 #include <unistd.h>
@@ -16,14 +16,14 @@
 const char *
 battery_perc(const char *bat)
 {
-#ifdef __linux__
+#if defined(__linux__)
 	int perc;
 	char path[PATH_MAX];
 
 	snprintf(path, sizeof(path), "%s%s%s", "/sys/class/power_supply/", bat, "/capacity");
 	return (pscanf(path, "%i", &perc) == 1) ?
 	       bprintf("%d", perc) : NULL;
-#elif __OpenBSD__
+#elif defined(__OpenBSD__)
 	struct apm_power_info apm_info;
 	int fd;
 
@@ -44,7 +44,7 @@ battery_perc(const char *bat)
 #endif
 }
 
-#ifdef __linux__
+#if defined(__linux__)
 const char *
 battery_power(const char *bat)
 {
diff --git a/components/cpu.c b/components/cpu.c
index ef27ec5..a001d14 100644
--- a/components/cpu.c
+++ b/components/cpu.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <stdio.h>
 #include <string.h>
 
diff --git a/components/entropy.c b/components/entropy.c
index f1441b3..65c65a1 100644
--- a/components/entropy.c
+++ b/components/entropy.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <stdio.h>
 
 #include "../util.h"
diff --git a/components/ip.c b/components/ip.c
index 8a40cfe..25071e4 100644
--- a/components/ip.c
+++ b/components/ip.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <err.h>
 #include <ifaddrs.h>
 #include <netdb.h>
diff --git a/components/ram.c b/components/ram.c
index 334a203..a1fc3fe 100644
--- a/components/ram.c
+++ b/components/ram.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <stdio.h>
 
 #include "../util.h"
diff --git a/components/swap.c b/components/swap.c
index a030f5f..0aad074 100644
--- a/components/swap.c
+++ b/components/swap.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <err.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/components/temperature.c b/components/temperature.c
index 6376e30..4a447e5 100644
--- a/components/temperature.c
+++ b/components/temperature.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <stdio.h>
 
 #include "../util.h"
diff --git a/components/uptime.c b/components/uptime.c
index c5e28ee..8a04b92 100644
--- a/components/uptime.c
+++ b/components/uptime.c
@@ -1,8 +1,8 @@
 /* See LICENSE file for copyright and license details. */
 #include <stdio.h>
-#ifdef __linux__
+#if defined(__linux__)
 #include <sys/sysinfo.h>
-#elif __OpenBSD__
+#elif defined(__OpenBSD__)
 #include <sys/sysctl.h>
 #include <sys/time.h>
 #endif
@@ -15,12 +15,12 @@ uptime(void)
 	int h;
 	int m;
 	int uptime = 0;
-#ifdef __linux__
+#if defined(__linux__)
 	struct sysinfo info;
 
 	sysinfo(&info);
 	uptime = info.uptime;
-#elif __OpenBSD__
+#elif defined(__OpenBSD__)
 	int mib[2];
 	size_t size;
 	time_t now;
diff --git a/components/volume.c b/components/volume.c
index a4b49bb..22fa02f 100644
--- a/components/volume.c
+++ b/components/volume.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <err.h>
 #include <fcntl.h>
 #include <sys/soundcard.h>
diff --git a/components/wifi.c b/components/wifi.c
index 084ab99..a02c277 100644
--- a/components/wifi.c
+++ b/components/wifi.c
@@ -1,5 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#ifdef __linux__
+#if defined(__linux__)
 #include <err.h>
 #include <ifaddrs.h>
 #include <linux/wireless.h>