temp: Put sysctl into define to avoid line wraps

Long, wrapped, multi-line if statements suck to read.
This fixes readability.

components/temperature.c

@@ -53,6 +53,8 @@
 	#include <stdlib.h>
 	#include <sys/sysctl.h>
 
+	#define ACPI_TEMP "hw.acpi.thermal.%s.temperature"
+
 	const char *
 	temp(const char *zone)
 	{
@@ -61,8 +63,8 @@
 		size_t len;
 
 		len = sizeof(temp);
-		snprintf(buf, sizeof(buf), "hw.acpi.thermal.%s.temperature", zone);
-		if (sysctlbyname(buf, &temp, &len, NULL, 0) == -1
+		snprintf(buf, sizeof(buf), ACPI_TEMP, zone);
+		if (sysctlbyname(buf, &temp, &len, NULL, 0) < 0
 				|| !len)
 			return NULL;