Problem compiling with gcc-4.1.2

Hello,

I tried to compile ddd-3.3.11 on an almost new install of Slackware
11.0 and the compile failed with the following errors:

---errors---
/usr/X11R6/include/X11/VendorP.h:87: error: previous declaration of
'VendorShellClassRec vendorShellClassRec' with 'C++' linkage
/usr/X11R6/include/Xm/VendorSP.h:58: error: conflicts with new
declaration with 'C' linkage
make[2]: *** [ScrolledGE.o] Error 1
make[2]: Leaving directory `/home/cb/src/Development/ddd-3.3.11/ddd'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/home/cb/src/Development/ddd-3.3.11/ddd'
make: *** [all-recursive] Error 1
---errors---

The system is a fully patched Slackware 11.0 on a core duo laptop.
Slackware 11.0 by default runs with xorg 6.9.0.

I have hand compiled gcc 4.1.2 after all the other slackware patches
were applied.  The compile was done with

gcc -v reports

---gcc -v---
Using built-in specs.
Target: i686-slackware-linux
Configured with: ../gcc-4.1.2/configure --enable-shared
--enable-threads=posix --enable-__cxa_atexit --disable-checking
--with-gnu-ld --verbose
--enable-languages=c,c++,fortran,objc,java,obj-c++,treelang
--target=i686-slackware-linux --host=i686-slackware-linux
--with-tune=prescott --with-arch=prescott --with-cpu=prescott
--prefix=/usr
Thread model: posix
gcc version 4.1.2
---gcc -v---

The relevant lines in the xorg include files that gcc-4.1.2 complains about are

---/usr/X11R6/include/X11/VendorP.h:87:---
externalref VendorShellClassRec vendorShellClassRec;
---/usr/X11R6/include/X11/VendorP.h:87:---

and

---/usr/X11R6/include/Xm/VendorSP.h:58:---
XMLIBEXPORT extern VendorShellClassRec  vendorShellClassRec;
---/usr/X11R6/include/Xm/VendorSP.h:58:---

If I compile with gcc-3.4.6 it all works fine, it's just strange that
this is the first program that didn't compile for me under gcc-4.1.2

Cheers

Carl

-- 
Carl Bartels

As a chemist, I find it annoying that spell checkers tend not to
recognize the words "titration" or "titrant", but I do find the
typical suggestions that computers come up with amusing.