LibC: add stubs for a lot of functions

libc/include/stdio.h

@@ -1,13 +1,42 @@
 #pragma once
 
+#include <stddef.h>
+#include <stdarg.h>
 #include <sys/cdefs.h>
+#include <sys/types.h>
 
 #define EOF (-1)
 
+#define stdin stdin
+#define stdout stdout
+#define stderr stderr
+
+#define SEEK_CUR 0
+#define SEEK_END 1
+#define SEEK_SET 2
+
 __BEGIN_DECLS
 
-int printf(const char* __restrict, ...);
+struct FILE;
+typedef struct FILE FILE;
+
+extern FILE* stdin;
+extern FILE* stdout;
+extern FILE* stderr;
+
+FILE* fopen(const char* __restrict__, const char* __restrict__);
+int fclose(FILE*);
+int fflush(FILE*);
+int fprintf(FILE* __restrict__, const char* __restrict__, ...);
+int fseek(FILE*, long, int);
+int printf(const char* __restrict__, ...);
 int putchar(int);
 int puts(const char*);
+int vfprintf(FILE* __restrict__, const char* __restrict__, va_list);
+long ftell(FILE*);
+size_t fread(void* __restrict__, size_t, size_t, FILE*);
+size_t fwrite(void const* __restrict__, size_t, size_t, FILE*);
+void setbuf(FILE* __restrict__, char* __restrict__);
+int sprintf(char* __restrict__, const char* __restrict__, ...);
 
-__END_DECLS
+__END_DECLS

libc/include/stdlib.h

@@ -1,14 +1,21 @@
 #pragma once
 
-#include <sys/cdefs.h>
 #include <stddef.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
-__attribute__((__noreturn__))
-void abort(void);
+[[noreturn]] void abort(void);
+
+int abs(int);
+
+int atexit(void(*)(void));
+int atoi(const char*);
+
+char* getenv(const char*);
 
 void* malloc(size_t);
+void* calloc(size_t, size_t);
 void free(void*);
 
 __END_DECLS

libc/include/string.h

@@ -6,7 +6,7 @@
 __BEGIN_DECLS
 
 int memcmp(const void*, const void*, size_t);
-void* memcpy(void* __restrict, const void* __restrict, size_t);
+void* memcpy(void* __restrict__, const void* __restrict__, size_t);
 void* memmove(void*, const void*, size_t);
 void* memset(void*, int, size_t);
 size_t strlen(const char*);
@@ -14,8 +14,12 @@ size_t strlen(const char*);
 int strcmp(const char*, const char*);
 int strncmp(const char*, const char*, size_t);
 
-char* strcpy(char* __restrict, const char* __restrict);
-char* strncpy(char* __restrict, const char* __restrict, size_t);
+char* strcpy(char* __restrict__, const char* __restrict__);
+char* strncpy(char* __restrict__, const char* __restrict__, size_t);
+
+char* strcat(char* __restrict__, const char* __restrict__);
+
+char* strchr(const char*, int);
 
 char* strstr(const char*, const char*);
 

libc/include/unistd.h

@@ -1,5 +1,21 @@
 #pragma once
 
+#include <sys/types.h>
+
 #define STDIN_FILENO 0
 #define STDOUT_FILENO 1
 #define STDERR_FILENO 2
+
+// fork(), execv(), execve(), execvp(), getpid()
+
+__BEGIN_DECLS
+
+pid_t fork(void);
+
+int execv(const char*, char* const[]);
+int execve(const char*, char* const[], char* const[]);
+int execvp(const char*, char* const[]);
+
+pid_t getpid(void);
+
+__END_DECLS