Hello All,

Some plugins (including MELT, see http://gcc-melt.org/ for more)
are made of several C++ source files which all include "plugin-version.h"
because they have some C++ code which depends upon the particular version 
of GCC.

So they typically code

  #if GCCPLUGIN_VERSION >= 4009
     /* code for GCC 4.9 or newer. */
  #else 
     /* code for GCC 4.8 */
  #endif /*GCCPLUGIN_VERSION*/

after including "plugin-version.h"; however that file also defines static
data, notably `gcc_version`. That data symbol may be useless in most of 
the plugin files -except the one initializing the plugin. Having several
useless data symbols may disturb the debugger (since the static symbol
`gcc_version` is no longer unique) and may consume some tiny useless data
(at least when the plugin is compiled with -O0).

The attached small patch (for trunk svn rev. 217404) disables the definition 
of `gcc_version` when the preprocessor symbol GCCPLUGIN_SKIP_VERSION_DATA 
is defined as 1 before #include "plugin-version.h"

### gcc/ChangeLog entry:

2014-11-12  Basile Starynkevitch  <basile@starynkevitch.net>

	* configure.ac (plugin-version.h): Don't define version data 
	when GCCPLUGIN_SKIP_VERSION_DATA was #define-d as 1.

	* doc/plugins.texi: (Plugins building): Document 
	GCCPLUGIN_SKIP_VERSION_DATA. Put it with GCCPLUGIN_VERSION* names
	in the function index.

###################

Ok for trunk? Comments are welcome.

Regards

-- 
Basile Starynkevitch     http://starynkevitch.net/Basile