lib: c: combine libc and ulibc

libc is now made up of several independent components, each of which is individually compiled into a static library.
they are then all combined into a single shared library.

lib/libc/include/stdlib.h

@@ -0,0 +1,13 @@
+#ifndef STDLIB_H_
+#define STDLIB_H_
+
+#include <stddef.h>
+
+extern void abort(void);
+
+extern void *malloc(size_t count);
+extern void *calloc(size_t count, size_t size);
+extern void *realloc(void *p, size_t count);
+extern void free(void *p);
+
+#endif