Carlo Bramini 2010-01-27 10:06:17 PST
When building third party software powered by libtool (like xine-lib and
several others) under Mingw+MSys, libSDL fails to link.
I got this message when building SDL video out component of xine-lib:

*** Warning: linker path does not have real file for library -lmingw32.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have
*** because I did check the linker path looking for a file starting
*** with libmingw32 and none of the candidates passed a file format test
*** using a file magic. Last file checked: /mingw/lib/libmingw32.a

Apparently there is no need to manually add -lmingw32 for making libSDL
working.
If this flag is removed, everything is built without troubles.
If it has been added for fixing a cross-compiler, perhaps if would be a better
idea to adjust its SPECS file in the same manner it has been done in the true
one used by mingw on Windows (I'm just guessing why it exists here).

There is also another message received on the console:

*** Warning: linker path does not have real file for library -lSDLmain.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have
*** because I did check the linker path looking for a file starting
*** with libSDLmain and none of the candidates passed a file format test
*** using a file magic. Last file checked: /mingw/lib/libSDLmain.a

This message, like previous one, is caused by -no-undefined flag sent to
libtool when building shared libraries.
Actually adding an .la file with its dependencies solves the troubles, so I
believe it would be better to create it too in the build process of libSDL.