libc: Document the functions in luna.h

libs/libc/include/luna.h

@@ -9,8 +9,13 @@ extern "C"
 {
 #endif
 
+    /* Returns the current program's thread identifier. */
     pid_t gettid();
-    unsigned int msleep(unsigned int);
+
+    /* Sleeps for ms milliseconds. */
+    unsigned int msleep(unsigned int ms);
+
+    /* Prints a message to standard error and aborts the program. */
     noreturn void __luna_abort(const char* message);
 
 #ifdef __cplusplus

libs/libc/src/luna.cpp

@@ -5,8 +5,6 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
-#define noreturn __attribute__((noreturn))
-
 extern "C"
 {
     pid_t gettid()
@@ -21,7 +19,7 @@ extern "C"
 
     noreturn void __luna_abort(const char* message)
     {
-        fwrite(message, strlen(message), 1, stdout);
+        fputs(message, stderr);
         abort();
     }
 }