Planning to promote raudio module as a simple and easy-to-use front-end for the amazing mini_al library, so the name change.

Name comes from raylib-audio but in spanish it also remembers to word "raudo", meaning  "very fast", an analogy that fits perfectly to the usefulness and performance of the library!

Consequently, raylib version has been bumped to 2.4-dev.

OPENGL_VERSION is the version requested by the user,
not the detected one...

Fixes #660.

A single warning at configuration time is enough.

The GLFW tree distributed with raylib has two modifications:

- GLFW_PKG_{DEPS,LIBS} are exported to PARENT_SCOPE, so we can use them
  in our pkg-config file
- An intermediary glfw_objlib target is added, so we can reexport GLFW
  symbols from libraylib.a

rglfw can fix the second point, but for Wayland usage, we would have to
replicate protocol generation, so we just leverage GLFW's existing
support instead.

To make maintenance easier, I have submitted a pull request for
including these modifications to upstream GLFW.
And to make that one easier, this patch dog-foods the modifications,
so raylib users can help find regressions. :-)

glfw/glfw#1307

So user code can use add_subdirectory to build it (similar to what we do
with GLFW or what the projects/CMake/CMakeLists.txt can do).

The CMakeLists.txt checks for an installed raylib and downloads and
installs one if none is found. Afterwards, it builds core_basic_window.c

Remove that link_libraries_to_executable() hack and defines a proper
raylib target that can be used with target_link_libraries.

The same target is also available for external (user) code by using
find_package(raylib).

This results in:

- Remove hardcoded build directories from examples and games CMakeLists.txt
- Allow rlgl_standalone and other special examples to be built easily
- Allow CMake projects to find_package(raylib instead of fiddling with pkg-config
- Makes code a little more maintainable
- Fixes #471, #606.
- Makes code less confusing by removing the double use of PLATFORM (#584).

Note that this is still not _The Right Way_(TM), because normally
raylib-config.cmake (or its includes) would be automatically generated.
I didn't manage to get that to work though, so I went the easier route
of just wrapping pkg_check_modules for consumption by find_package.

pkg-config --libs --static raylib and pkg-config --libs raylib
should give the same result if there is no shared raylib installed.

if (${PLATFORM} MATCHES "Desktop")
  target_link_libraries(${RAYLIB}_shared glfw ${GLFW_LIBRARIES})

was never true because PLATFORM STREQUAL "PLATFORM_DESKTOP"...

This fixes #551 and makes the changes suggested in #552 (commited as 965cc8ab)
unnecessary.

Fixes: e1e036a6 ("Disable glfw only when it is not found and not external", #558)

Did this ever work? Surely, doesn't look like it...

Not sure if this ever worked, but now it at least compiles.

Release, unless we are in a Git repo, then it's Debug.

Please do this whenever necessary. And adapt it before releasing a new
RC. The RC should already have the correct one.

This reverts commit 2d6fb5c628068757387525e190c3afdbe33ae9c6,
and adds a fix for Alien::raylib's test failures.

The tests failed because the resulting static library didn't reexport
GLFW symbols. As a fix, we now have GLFW create a CMake "object library"
target that we can link with both the static and shared raylib.

This is arguably ugly... Proper fix would probably be a GLFW upstream
object library target.

Closes #536.

This reverts commit 0adb4b67de6dfe3f7a0a557130dffc3b8f4d6a43,
because it failed tests for Alien::raylib:
http://www.cpantesters.org/distro/A/Alien-raylib.html

Review raylib_icon resource

Makes it easier to support Wayland later on.

Panders to the idiosyncrasies of my work flow:
I have my raylib build directory mounted as a VirtualBox vboxfs for use
with my Linux VM, but vboxfs doesn't support symlinks, while raylib shared
library versioning on Unix expects symlinks to work.
If this happens, library versioning is now disabled on Unix with
an error message instead of just failing the build.

I would have liked config.h to be selected by include dir configuration,
but this way is less intrusive.

To make bugs like #485, #486, #487 and #488 easier to find in future.

They were named so for compatibility with make, but make doesn't use
the anymore. I always forget whether it's SHARED_RAYLIB or
RAYLIB_SHARED...

For now, RAYLIB_SHARED and STATIC_RAYLIB may still be used,
but print a deprecation warning.

If user doesn't build the static library,
`pkg-config --static --libs raylib` should be equivalent to
`pkg-config --libs raylib`.

-DWITH_SYSTEM_GLFW=ON: Link against system glfw and fail otherwise
-DWITH_SYSTEM_GLFW=OFF: Use embedded rglfw.c
-DWITH_SYSTEM_GLFW=IF_POSSIBLE: Probe for system glfw but fallback to
                                rglfw if unavailable

Also change Linux 64-bit CI build to install system glfw and use it,
so this doesn't bitrot.

Addresses #453.

See #401 for the discussion.
Also bumps version number to 1.9.2 without the -dev,
because neither ELF nor MachO like such a suffix.
The -dev suffix will have to be restricted to the git tags.

OpenAL Soft backend is still available in audio module, I'm thinking if
exposing it for building in some way or just left it there for advance
users to switch to it manually in case of necessity...