The new Raspberry Pi 4B revision has a minimum requirement of Raspbian
buster, and uses the Mesa V3D driver by default; in fact, the legacy
Broadcom drivers are no longer compatible with its VideoCore VC6 chip, so
building against Mesa is mandatory for this Pi revision.
Unfortunately, the Debian buster version of the Mesa packages
have intentionally dropped the GLESv1 headers, making building of GLESv1
software impractical (even though the VC4/V3D driver can still run GLESv1
applications).
The OpenGL driver in conjunction with SDL2* runs at full
speed on Raspberry Pi 3B & 4B, so it makes sense to modify the "mesa"
build to this configuration in light of these facts.
* SDL2 is highly desirable due to the availability of the KMSDRM driver, which is
the only way to run dxx-rebirth outside of X (we can no longer use
the dispmanx/rpi driver of SDL1).
For each link given as http://, verify that the site is accessible over
https:// and, if so, switch to it. These domains were converted:
* llvm.org
* clang.llvm.org
* en.cppreference.com
* www.dxx-rebirth.com
* www.libsdl.org
* www.scons.org
Vendor library has new names to avoid conflicts with Mesa. Update
raspberrypi argument to use new libraries and support Mesa VC4 driver.
* raspberrypi=1 will build against the (newly named) vendor libraries
* raspberrypi=mesa will target building against the VC4 driver.
Both will select GLES by default, but you can target GL for the VC4 driver
via "raspberrypi=mesa opengles=0"
