egl: Native Display autodetection

EGL doesnt define howto manage different native platforms.
So mesa has a builtime configurable default platform,
whith non-standard envvar (EGL_PLATFORM) overwrites.
This caused unneeded bugreports, when EGL_PLATFORM was forgotten.

Detection is grouped into basic types of NativeDisplays (which itself
needs to be detected).  The final decision is based on characteristcs
of these basic types:

  File Desciptor based platforms (fbdev):
    - fstat(2) to check for being a fd that belongs to a character device
    - check kernel subsystem (todo)

  Pointer to structuctures (x11, wayland, drm/gbm):
    - mincore(2) to check whether its valid pointer to some memory.
    - magic elements (e.g. pointers to exported symbols):
      o wayland display stores interface type pointer (first elm.)
      o gbm stores pointer to its constructor (first elm.)
      o x11 as a fallback (FIXME?)

Reviewed-by: Kristian Høgsberg <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/egl/main/Makefile b/src/egl/main/Makefile
index 775fbbe178b..c100fbfeb9c 100644
--- a/src/egl/main/Makefile
+++ b/src/egl/main/Makefile
@@ -93,6 +93,19 @@ ifeq ($(firstword $(EGL_PLATFORMS)),fbdev)
 EGL_NATIVE_PLATFORM=_EGL_PLATFORM_FBDEV
 endif
 
+ifneq ($(findstring x11, $(EGL_PLATFORMS)),)
+LOCAL_CFLAGS += -DHAVE_X11_PLATFORM
+endif
+ifneq ($(findstring wayland, $(EGL_PLATFORMS)),)
+LOCAL_CFLAGS += -DHAVE_WAYLAND_PLATFORM
+endif
+ifneq ($(findstring drm, $(EGL_PLATFORMS)),)
+LOCAL_CFLAGS += -DHAVE_DRM_PLATFORM
+endif
+ifneq ($(findstring fbdev, $(EGL_PLATFORMS)),)
+LOCAL_CFLAGS += -DHAVE_FBDEV_PLATFORM
+endif
+
 LOCAL_CFLAGS += \
 	-D_EGL_NATIVE_PLATFORM=$(EGL_NATIVE_PLATFORM) \
 	-D_EGL_DRIVER_SEARCH_DIR=\"$(EGL_DRIVER_INSTALL_DIR)\"