QFileSystemEngine: handle copy_file_range() returning ENOSYS error

This shouldn't have happened, because minimum-linux_p.h would have
declared our need for a Linux kernel 4.5 or higher. I think the issue is
not the kernel, but a container wrapping the Qt application and
filtering system calls for security. If this container hasn't been
updated to know about the system call, it may cause an ENOSYS error.

Because we now handle the condition, this commit removes the 4.5 minimum
Linux version requirement from minimum-linux_p.h.

[ChangeLog][QtCore][QFile] Added a workaround to a compatibility issue
of the copy() implementation in some containerized Linux environments,
which could cause the file copy to fail with a "Function not
implemented" error. This is believed to be a bug in the container
runtime, not Qt, in that the container wrongly filtered the
copy_file_range(2) system call that the Linux kernel supports.

Fixes: QTBUG-144142
Pick-to: 6.11 6.10
Change-Id: Iedbf805486ad79e7127dfffd22043889359563fd
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>

Author: thiagomacieira

src/corelib/global/minimum-linux_p.h

@@ -41,7 +41,6 @@ QT_BEGIN_NAMESPACE
  * - accept4                    2.6.28
  * - renameat2                  3.16                    QT_CONFIG(renameat2)
  * - getrandom                  3.17                    QT_CONFIG(getentropy)
- * - copy_file_range            4.5                     QT_CONFIG(copy_file_range)
  * - statx                      4.11                    STATX_BASIC_STATS
  */
 
@@ -51,10 +50,6 @@ QT_BEGIN_NAMESPACE
 #  define QT_ELF_NOTE_OS_MAJOR      4
 #  define QT_ELF_NOTE_OS_MINOR      11
 #  define QT_ELF_NOTE_OS_PATCH      0
-#elif QT_CONFIG(copy_file_range)
-#  define QT_ELF_NOTE_OS_MAJOR      4
-#  define QT_ELF_NOTE_OS_MINOR      5
-#  define QT_ELF_NOTE_OS_PATCH      0
 #elif QT_CONFIG(getentropy)
 #  define QT_ELF_NOTE_OS_MAJOR      3
 #  define QT_ELF_NOTE_OS_MINOR      17

src/corelib/io/qfilesystemengine_unix.cpp

@@ -1204,6 +1204,7 @@ auto QFileSystemEngine::cloneFile(int srcfd, int dstfd, const QFileSystemMetaDat
     switch (errno) {
     case EINVAL: // observed with some obscure filesystem combinations
     case EXDEV: // Linux can't do xdev file copies (FreeBSD can)
+    case ENOSYS: // caused by some containers wrongly filtering the system call
         break;
 
     default: