diff --git a/configure.ac b/configure.ac
index 15f1131df..de8a6d210 100644
--- a/configure.ac
+++ b/configure.ac
@@ -70,7 +70,7 @@ dnl glibc 2.25 deprecates 'major' and 'minor' in <sys/types.h> and requires to
 dnl include <sys/sysmacros.h>. However the logic in AC_HEADER_MAJOR has not yet
 dnl been updated in Autoconf 2.69, so use a workaround:
 m4_version_prereq([2.70], [],
-[if test "x$ac_cv_header_sys_mkdev_h" = xno; then
+[if test "x$ac_cv_header_sys_mkdev_h" != xyes; then
    AC_CHECK_HEADER(sys/sysmacros.h, [AC_DEFINE(MAJOR_IN_SYSMACROS, 1,
       [Define to 1 if `major', `minor', and `makedev' are declared in <sys/sysmacros.h>.])])
 fi])
diff --git a/linux/LinuxProcess.c b/linux/LinuxProcess.c
index 7fa67a90a..df94f04da 100644
--- a/linux/LinuxProcess.c
+++ b/linux/LinuxProcess.c
@@ -401,7 +401,7 @@ static inline void LinuxProcess_printPerfCounter(float val, int len, char* buffe
    if (val != -1) {
       xSnprintf(buffer, n, perfFmt[len], val);
    } else {
-      xSnprintf(buffer, n, perfNA[len]);
+      xSnprintf(buffer, n, "%s", perfNA[len]);
       *attr = CRT_colors[PROCESS_SHADOW];
    }
 }