[USER] brk syscall

kernel/include/process.h

@@ -62,5 +62,6 @@ void procmm_free_map(process_t *proc);
 void procmm_print_map(procmm_mmap_t *map);
 procmm_area_t *procmm_map(procmm_mmap_t *map, uintptr_t start, uintptr_t end, uint64_t flags);
 void procmm_unmap(procmm_area_t *a);
+size_t procmm_resize(process_t *p, procmm_area_t *a, size_t len);
 int procmm_setup(process_t *proc, size_t brk_size);
 registers_t *procmm_page_fault(registers_t *r);

kernel/include/syscall.h

@@ -41,3 +41,4 @@ typedef long (*syscall_handler_t)(long num, long, long, long, long, long, long);
 #define SYSCALL_REGISTER(name, num) syscall_handlers[num] = syscall_##name
 
 SYSCALL_DECL(write);
+SYSCALL_DECL(brk);