Runtime/math matches; better libc headers

Former-commit-id: bef7db1748

libc/stdlib.h

@@ -0,0 +1,25 @@
+#ifndef _STDLIB_H_
+#define _STDLIB_H_
+
+#include <stddef.h>
+#include <wchar.h>
+
+#define RAND_MAX 32767
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void srand(unsigned int seed);
+int rand(void);
+void exit(int status);
+size_t wcstombs(char* dest, const wchar_t* src, size_t max);
+
+typedef int (*_compare_function)(const void*, const void*);
+void qsort(void*, size_t, size_t, _compare_function);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif