Merge pull request #732 from aliaspider/master

(PSP) implemented salamander and added support for switching between cores.
(Salamander) Use EXT_EXECUTABLES
(Salamander) Refactorings - Salamander should be easier to get to
work now on new console platforms
(PSP) Cleanup frontend_psp_exitspawn
(XDK/GX) Cleanups to exitspawn implementations
Use PKG_CONF_PATH in qb/.
Fix multiword --with- arguments.
Add initial Mali FBdev support.
Check for libudev as plain lib as well.
Add EXTRA_GL_LIBS to libretro-test-gl.
Fix unknown hang in Mali fbdev.
Auto-enable some extensions if GLES3.
Use correct arguments if sRGB and GLES3.
Merge pull request #733 from libretro/mali-fbdev

Mali fbdev
Merge pull request #2 from libretro/master

update this one
Add memory descriptor interface to libretro.h, for use with cheats.
Merge pull request #734 from Alcaro/master

Add memory descriptor interface to libretro.h, for use with cheats.
(Lakka) Style nits
Create public init_menu/uninit_menu
(Lakka) More cleanups