diff --git a/include/unistd.h b/include/unistd.h
index 4b2666a10e..4b2b89f6ec 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -45,7 +45,6 @@
 #define POSIX_VERSION
 #undef  _POSIX_SAVED_IDS
 #undef  _POSIX_JOB_CONTROL
-#define _POSIX_REALTIME_SIGNALS 1
 #define _POSIX_MESSAGE_PASSING 1
 #undef  _POSIX_MAPPED_FILES
 #undef  _POSIX_SHARED_MEMORY_OBJECTS
@@ -65,6 +64,7 @@
 #define _POSIX_PRIORITIZED_IO _POSIX_VERSION
 #define _POSIX_CPUTIME _POSIX_VERSION
 #define _POSIX_THREAD_CPUTIME _POSIX_VERSION
+#define _POSIX_REALTIME_SIGNALS _POSIX_VERSION
 #define _POSIX_THREAD_PRIORITY_SCHEDULING _POSIX_VERSION
 
 #ifdef CONFIG_FS_AIO
diff --git a/libs/libc/unistd/lib_sysconf.c b/libs/libc/unistd/lib_sysconf.c
index f0fde4bfe2..eff4e718e2 100644
--- a/libs/libc/unistd/lib_sysconf.c
+++ b/libs/libc/unistd/lib_sysconf.c
@@ -227,6 +227,8 @@ long sysconf(int name)
         return _POSIX_CPUTIME;
       case _SC_THREAD_CPUTIME:
         return _POSIX_THREAD_CPUTIME;
+      case _SC_REALTIME_SIGNALS:
+        return _POSIX_REALTIME_SIGNALS;
       case _SC_CLK_TCK:
         return CLOCKS_PER_SEC;