bug#12058: AM_PATH_SDL does not find SDL framework installations on Mac OSX

[David Lowe]

        Background information: on OSX, the preferred distribution method for 
libraries is the 'framework' which is a click-and-draggable object that 
contains headers and libraries together.  The standard location for these is: 
/Library/Frameworks/

        I have the latest version of officially provided SDL runtime libraries 
here:

Darlene-Lowes-Mac-mini:/ (222) $ ls /Library/Frameworks/SDL*
/Library/Frameworks/SDL.framework:
Headers   Resources SDL       Versions

/Library/Frameworks/SDL_image.framework:
Frameworks Headers    Resources  SDL_image  Versions

/Library/Frameworks/SDL_mixer.framework:
Frameworks Headers    Resources  SDL_mixer  Versions

        However, automake ignores them, leading to:

checking for sdl-config... no
checking for SDL - version >= 1.1.4... no
*** The sdl-config script installed by SDL could not be found
*** If SDL was installed in PREFIX, make sure PREFIX/bin is in
*** your path, or set the SDL_CONFIG environment variable to the
*** full path to sdl-config.
configure: error: specified client 'sdl' not configurable (SDL >= 1.1.4 is 
needed (www.libsdl.org))

        The above portion of a log came from a recent attempt to install 
Freeciv-SDL from source.  I will attach the full copies of configure.ac and 
Makefile.am that were generated during that attempt, as i don't know enough to 
be sure what i could trim out without removing useful information.  In any 
case, the failure is repeatable across a range of versions of OSX with these 
frameworks.  I did once grab the SDL sources and do the usual configure/make.  
The resulting installation does not create a framework, but automake does find 
the libraries.

configure.ac
Description: Binary data

Makefile.am
Description: Binary data

        Relevant versions:

automake: 1.10
SDL: 1.2.14
OSX: 10.6.8

        Desired results: I would prefer that AM_PATH_SDL be upgraded to find 
and use such frameworks.  Failing that, it would be nice if someone could 
suggest an alternate test so that the framework can be used in the configure 
process of the Freeciv project.