Kernel/LibC: Implement fsync

userspace/libraries/LibC/include/sys/syscall.h

@@ -85,6 +85,7 @@ __BEGIN_DECLS
 	O(SYS_SETITIMER,		setitimer)		\
 	O(SYS_POSIX_OPENPT,		posix_openpt)	\
 	O(SYS_PTSNAME,			ptsname)		\
+	O(SYS_FSYNC,			fsync)			\
 
 enum Syscall
 {

userspace/libraries/LibC/unistd.cpp

@@ -115,6 +115,11 @@ int ftruncate(int fildes, off_t length)
 	return syscall(SYS_TRUNCATE, fildes, length);
 }
 
+int fsync(int fildes)
+{
+	return syscall(SYS_FSYNC, fildes);
+}
+
 int dup(int fildes)
 {
 	return syscall(SYS_DUP, fildes);