Upload current libxunil, to be used as a submodule

include/stdlib.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <inttypes.h>
+#include <stddef.h>
+
+void  *malloc(size_t size);
+void  *calloc(size_t nmemb, size_t size);
+void  *realloc(void *ptr, size_t size);
+void   free(void *ptr);
+
+void   exit(int status);
+void   abort(void);
+
+int    atoi(const char *s);
+long   atol(const char *s);
+double atof(const char *s);
+long   strtol(const char *s, char **endptr, int base);
+double strtod(const char *s, char **endptr);
+
+char  *getenv(const char *name);
+void   qsort(void *base, size_t nmemb, size_t size, int (*cmp)(const void *, const void *));
+int    abs(int x);
+int    system(const char *cmd);
+int    draw_pixel(uint32_t x, uint32_t y, uint32_t color);
+int    framebuffer_swap();