"warning: declaration of '<something>' shadows a member of 'this'

This shows up in gcc 4.8.5 and has been fixed in gcc 5.0, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57709

Change the variable names anyway to be on the safe side.

Fixes ArcticaProject/nx-libs#958

In file included from Proxy.h:39:0,
                 from ServerProxy.h:32,
                 from ServerProxy.cpp:36:
Channel.h: In member function 'int Channel::handleEncodeIdentity(EncodeBuffer&, ChannelCache*, MessageStore*, const unsigned char*, unsigned int, int)':
Channel.h:369:3: warning: declaration of 'bigEndian' shadows a member of 'this' [-Wshadow]
   {
   ^
Channel.h: In member function 'int Channel::handleDecodeIdentity(DecodeBuffer&, ChannelCache*, MessageStore*, unsigned char*&, unsigned int&, int, WriteBuffer*)':
Channel.h:378:3: warning: declaration of 'bigEndian' shadows a member of 'this' [-Wshadow]
   {
   ^

RHEL7's g++ 4.8.5 reports this while Debian's g++ 10.2.0-15 does
not. This is described in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57709 and fixed in gcc
5.0.

Rename the variables anyway to be on the safe side.

Fixes ArcticaProject/nx-libs#956

*** ERROR: ambiguous python shebang in /usr/bin/nxdialog: #!/usr/bin/env
python. Change it to python3 (or python2) explicitly.

Fedora offers a pythfix.py but I could not test with that so I simply
used sed...

Fixes ArcticaProject/nx-libs#955

Attributes GH PR #949: https://github.com/ArcticaProject/nx-libs/pull/949

==15332== 2,500 (96 direct, 2,404 indirect) bytes in 6 blocks are definitely lost in loss record 324 of 342
==15332==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==15332==    by 0x5748B9E: FontFileStartListFonts (in /usr/lib/x86_64-linux-gnu/libXfont.so.1.4.1)
==15332==    by 0x5748C4A: FontFileStartListFontsAndAliases (in /usr/lib/x86_64-linux-gnu/libXfont.so.1.4.1)
==15332==    by 0x42859A: nxdoListFontsAndAliases (NXdixfonts.c:1163)
==15332==    by 0x42C0E0: nxOpenFont (NXdixfonts.c:1541)
==15332==    by 0x43392E: ProcOpenFont (NXdispatch.c:902)
==15332==    by 0x434585: Dispatch (NXdispatch.c:482)
==15332==    by 0x40EF77: main (main.c:355)

FontFileStartListFonts[AndAliases]() allocates some private data. This
data is used by subsequent calls of FontFileListNextFontOrAlias() in a
loop. (Only) the last call to that function will free() the private
data and return with BadFontName.  FontFileListNextFontOrAlias() is
the only libXfont function that free()s the private data.

In nxagent the loop is exited as soon as a font exists both locally
and remote. Therefore the private data would never be free()d.

Solution: do not break the loop but store the first matching result
and let the loop run to the end, ignoring all following results.

Disadvantage: this can mean hundreds of extra iterations for
nothing. I have done no investigation of the time penalty this might
cause.

Unfortunately this is the only clean way I have found so far.

An unclean solution has also been implemented. It can be activated by
defining BREAK_XFONT_LOOP. In that case the private data is handled in
nxagent by taking assumptions about its structure (taken from the
libXfont source). That will break if libXfont changes its internal
handling of the private. Therefore it is discouraged.

An third alternative would be to drop using libXfont from the
system. Instead fork libXfont to the nx-libs tree, add some patches
link to that library statically.

Fixes ArcticaProject/nx-libs#586

Attributes GH PR #952: https://github.com/ArcticaProject/nx-libs/pull/952

 Direct leak of 3 byte(s) in 1 object(s) allocated from:
 #0 0xb79e85d4 in __interceptor_malloc (/lib/i386-linux-gnu/libasan.so.5+0xeb5d4)
 #1 0xb770b635 in copystring /home/uli/work/nx/nx-libs/nx-X11/lib/src/ConnDis.c:96
 #2 0xb770ba56 in _X11TransConnectDisplay /home/uli/work/nx/nx-libs/nx-X11/lib/src/ConnDis.c:229
 #3 0xb776b4fd in XOpenDisplay /home/uli/work/nx/nx-libs/nx-X11/lib/src/OpenDis.c:215
 #4 0x63e2fd in nxagentInternalOpenDisplay /home/uli/work/nx/nx-libs/nx-X11/programs/Xserver/hw/nxagent/Display.c:608
 #5 0x63fa03 in nxagentOpenDisplay /home/uli/work/nx/nx-libs/nx-X11/programs/Xserver/hw/nxagent/Display.c:1140
 #6 0x694b5a in InitOutput /home/uli/work/nx/nx-libs/nx-X11/programs/Xserver/hw/nxagent/Init.c:305
 #7 0x5f7b11 in main /home/uli/work/nx/nx-libs/nx-X11/programs/Xserver/dix/main.c:278
 #8 0xb6f04b40 in __libc_start_main ../csu/libc-start.c:308

I have not investigated the exact location where an XFree() was missing but added multiple
Xfree() calls whereever appropriate.

Fixes ArcticaProject/nx-libs#951

fix spec file

doc file path for nxdialog was wrong

Fixes ArcticaProject/nx-libs#959

Attributes GH PR #940: https://github.com/ArcticaProject/nx-libs/pull/940

Setting nxagentDefaultWindow[pScreen->myNum] is pointless because it is
overwritten in the next code block...

setting a value for an attribute in the structure is pointless if you
do not set the valuemask accordingly. Adding the missing valuemask
code here would also be pointless because the valuemask is set to a fixed
value later on. Therefore we can drop this code here.

new code is easier to read

and not as a "private" window like all others.

We are not using it anywhere so let's disable it via a macro for now.