Reports of Xonotic not launching on Mac OS 10.9 and 10.10, SDL2-related
I'm reporting issues seen on the forums. One user with Mac OS 10.9.5 (Mavericks) [reports the following error](http://forums.xonotic.org/showthread.php?tid=5248&pid=70281#pid70281) on launch:
````
Application Specific Information:
dyld: launch, loading dependent libraries
Dyld Error Message:
Library not loaded: @rpath/SDL2.framework/Versions/A/SDL2
Referenced from: /Users/USER/Downloads/*/Xonotic.app/Contents/MacOS/xonotic-osx-sdl-bin
Reason: image not found
Binary Images:
0x7fff6564a000 - 0x7fff6567d817 dyld (239.4) <7AD43B9B-5CEA-3C7E-9836-A06909F9CA56> /usr/lib/dyld
0x7fff8cf50000 - 0x7fff8cfbcfff com.apple.framework.IOKit (2.0.1 - 907.100.13) <057FDBA3-56D6-3903-8C0B-849214BF1985> /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
0x7fff929a1000 - 0x7fff929a2ff7 libSystem.B.dylib (1197.1.1) <E303F2F8-A8CF-3DF3-84B3-F2D0EE41CCF6> /usr/lib/libSystem.B.dylib
0x7fff97a13000 - 0x7fff97a24ff7 libz.1.dylib (53) <42E0C8C6-CA38-3CA4-8619-D24ED5DD492E> /usr/lib/libz.1.dylib
````
Another user using Mac OS 10.10.1 (Yosemite) [reports the following error](http://forums.xonotic.org/showthread.php?tid=5248&pid=70323#pid70323):
````
Process: xonotic-osx-sdl-bin [1108]
...
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000
...
Application Specific Information:
dyld: launch, loading dependent libraries
DYLD_LIBRARY_PATH=/Users/USER/Downloads/Xonotic/Xonotic.app/Contents/MacOS
Dyld Error Message:
Library not loaded: @rpath/SDL2.framework/Versions/A/SDL2
Referenced from: /Users/USER/Downloads/*/Xonotic.app/Contents/MacOS/xonotic-osx-sdl-bin
Reason: image not found
Binary Images:
0x7fff69c90000 - 0x7fff69cc6837 dyld (353.2.1) <4696A982-1500-34EC-9777-1EF7A03E2659> /usr/lib/dyld
0x7fff829e7000 - 0x7fff82a58ff7 com.apple.framework.IOKit (2.0.2 - 1050.1.21) <ED3B0B22-AACC-303B-BFC8-20ECD1AF6BA2> /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
0x7fff855d4000 - 0x7fff855e5ff7 libz.1.dylib (55) <88C7C7DE-04B8-316F-8B74-ACD9F3DE1AA1> /usr/lib/libz.1.dylib
0x7fff8c01a000 - 0x7fff8c01bfff libSystem.B.dylib (1213) <DA954461-EC6A-3DF0-8551-6FC810627627> /usr/lib/libSystem.B.dylib
````
issue