Kernel/LibC: Add basic pipe() syscall and command

You can now create pipes :)

libc/include/sys/syscall.h

@@ -39,6 +39,7 @@ __BEGIN_DECLS
 #define SYS_GET_PWD 32
 #define SYS_SET_PWD 33
 #define SYS_CLOCK_GETTIME 34
+#define SYS_PIPE 35
 
 __END_DECLS
 

libc/unistd.cpp

@@ -251,6 +251,12 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_CLOCK_GETTIME, clock_id, (uintptr_t)tp);
 			break;
 		}
+		case SYS_PIPE:
+		{
+			int* fildes = va_arg(args, int*);
+			ret = Kernel::syscall(SYS_PIPE, (uintptr_t)fildes);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;
@@ -365,6 +371,11 @@ pid_t fork(void)
 	return syscall(SYS_FORK);
 }
 
+int pipe(int fildes[2])
+{
+	return syscall(SYS_PIPE, fildes);
+}
+
 unsigned int sleep(unsigned int seconds)
 {
 	return syscall(SYS_SLEEP, seconds);