configure: remove HAVE_EGL_DRIVER_DRI[23]

We have them for local purposes in configure, where we can use their
direct dependency.

With the only remaining instance in the makefile(s) being always true,
as it can be seen in the configure snippet.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/configure.ac b/configure.ac
index ec28032..e162f9b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2012,14 +2012,8 @@
     fi
 
     if test "x$enable_dri" = xyes; then
-        HAVE_EGL_DRIVER_DRI2=1
         if test "x$enable_shared_glapi" = xno; then
-            AC_MSG_ERROR([egl_dri2 requires --enable-shared-glapi])
-        fi
-        if test "x$enable_dri3" = xyes; then
-            HAVE_EGL_DRIVER_DRI3=1
-            if test "x$enable_shared_glapi" = xno; then
-            AC_MSG_ERROR([egl_dri3 requires --enable-shared-glapi])
+            AC_MSG_ERROR([egl_dri requires --enable-shared-glapi])
         fi
     else
         # Avoid building an "empty" libEGL. Drop/update this
@@ -2299,8 +2293,6 @@
 AM_CONDITIONAL(HAVE_EGL_PLATFORM_SURFACELESS, echo "$egl_platforms" | grep -q 'surfaceless')
 AM_CONDITIONAL(HAVE_EGL_PLATFORM_ANDROID, echo "$egl_platforms" | grep -q 'android')
 
-AM_CONDITIONAL(HAVE_EGL_DRIVER_DRI2, test "x$HAVE_EGL_DRIVER_DRI2" != "x")
-
 AC_SUBST([EGL_NATIVE_PLATFORM])
 AC_SUBST([EGL_CFLAGS])
 
@@ -2941,10 +2933,10 @@
     echo "        EGL platforms:   $egl_platforms"
 
     egl_drivers=""
-    if test "x$HAVE_EGL_DRIVER_DRI2" != "x"; then
+    if test "x$enable_dri" != "xno"; then
         egl_drivers="$egl_drivers builtin:egl_dri2"
     fi
-    if test "x$HAVE_EGL_DRIVER_DRI3" != "x"; then
+    if test "x$enable_dri3" != "xno"; then
         egl_drivers="$egl_drivers builtin:egl_dri3"
     fi
 
diff --git a/src/egl/Makefile.am b/src/egl/Makefile.am
index 7c5abd2..78cf525 100644
--- a/src/egl/Makefile.am
+++ b/src/egl/Makefile.am
@@ -91,7 +91,6 @@
 dri2_backend_FILES += drivers/dri2/platform_android.c
 endif
 
-if HAVE_EGL_DRIVER_DRI2
 AM_CFLAGS += \
 	-I$(top_srcdir)/src/loader \
 	-I$(top_srcdir)/src/egl/drivers/dri2 \
@@ -109,7 +108,6 @@
 
 libEGL_la_LIBADD += $(top_builddir)/src/loader/libloader.la
 libEGL_la_LIBADD += $(DLOPEN_LIBS) $(LIBDRM_LIBS) $(CLOCK_LIB)
-endif
 
 include $(top_srcdir)/install-lib-links.mk