[CMake] IA64 HP-UX build failure

[Matthew Woehlke]

I get the following failure building cmake 2.4.6 on IA64 HP-UX, due to 
__attribute__ not being defined into nothingness:

====
...
[ 42%] Building C object 
Utilities/cmxmlrpc/CMakeFiles/cmXMLRPC.dir/xmlrpc_client.o
Error 20: 
"/home/install/gnu/src/cmake-2.4.6/Utilities/cmxmlrpc/xmlrpc_client.c", 
line 125 # ',' expected before '__attribute__'.
     xmlrpc_client_get_default_transport(xmlrpc_env * const env 
ATTR_UNUSED) {
                                                                ^^^^^^^^^^^
Error 42: 
"/home/install/gnu/src/cmake-2.4.6/Utilities/cmxmlrpc/xmlrpc_client.c", 
line 125 # ANSI C requires same function declarations to have compatible 
types. Previous function declaration
     was "const char *xmlrpc_client_get_default_transport(_xmlrpc_env 
*)" 
["/home/install/gnu/src/cmake-2.4.6/Utilities/cmxmlrpc/xmlrpc_client.h", 
line 64].
     xmlrpc_client_get_default_transport(xmlrpc_env * const env ATTR_
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error 341: 
"/home/install/gnu/src/cmake-2.4.6/Utilities/cmxmlrpc/xmlrpc_client.c", 
line 125 # ANSI C expects identifier name for parameter declaration.
     xmlrpc_client_get_default_transport(xmlrpc_env * const env 
ATTR_UNUSED) {
                                                                ^^^^^^^^^^^
make[2]: *** 
[Utilities/cmxmlrpc/CMakeFiles/cmXMLRPC.dir/xmlrpc_client.o] Error 2
make[1]: *** [Utilities/cmxmlrpc/CMakeFiles/cmXMLRPC.dir/all] Error 2
make: *** [all] Error 2
====

$ cc -V
cc: HP aC++/ANSI C B3910B A.05.50 [May 15 2003]
$ uname -srvmpio
HP-UX B.11.22 U ia64 unknown unknown HP-UX

...there is no gcc/g++ on this system.

-- 
Matthew
"Have you tried that new mixed drink, 'GDR'"?
"What is it?"
"Gin, Duck and Rum. It tastes fowl."