* added cross compilation options for DRM

* fixed identation

Reasons to NOT define `_GNU_SOURCE`:

 - access to lots of nonstandard GNU/Linux extension functions
 - access to traditional functions which were omitted from the POSIX standard (often for good reason, such as being replaced with better alternatives, or being tied to particular legacy implementations)
 - access to low-level functions that cannot be portable, but that you sometimes need for implementing system utilities like mount, ifconfig, etc.
 - broken behavior for lots of POSIX-specified functions, where the GNU folks disagreed with the standards committee on how the functions should behave and decided to do their own thing.

This linkage is only required for arm 32bit but I don't know how to detect that specific architecture in the Makefile...

* Fix Undefined Symbol `_ftelli64`

* Add files via upload

* Update raylib.h

* Update raylib.h

* test if clang supports multiple targets

* didnt work, so trying lipo to join separate targets together

* add CUSTOM_LDFLAGS to try to fix arm64 mac dynamic build

* fix sym links

* try again to fix sym links

* auto extract raylib version numbers from makefile

* fix macos missing gnu grep

* dont use custom name for raylib dlls

* Fixed an issue when using raygui and physac on unix systems
hash "#" is single-line comment character in bash so echo ignores #include and #define

* tab fix

* Properly fix make clean under sh.exe

* Ensure make clean works properly under Windows if RAYLIB_RELEASE_PATH is modified

This reverts commit ab47c6401e.

Tested on the following environments:
 - w64devkit.exe
 - Windows 10 cmd
 - Notepad++ NppExec console

GNU make on Windows first tries to find sh.exe on the path,
and will execute build rules using it if it is present.
The make clean target uses the builtin cmd.exe command del, which
won't work under sh.exe

The reason this is not done for the entire Makefile is because it would
break cross-compilation of raylib.

Justification: original comment said the following
"TODO: Add other platforms. Remove sudo requirement, i.e. add USER mode."

For the other platforms part, installing is included on unix-like
systems, so for example Windows doesn't have a path where to install
libraries.

Removing the requirement for sudo is also quite contradictory since
we're writing files to directories which require root. Not sure what the
original commiter meant by USER mode.

Built files should be put into src/ not into the project root
as it was now on these platforms

* Override CC while compiling for ANDROID_ARCH x86

* REfix Override CC while compiling

NOTE: New raylib release installer uses `w64devkit`, smaller and more updated than regular `mingw64-w64` default project. Paths are updated properly.