build: Enable EGL on Android

It's the only platform specific API it has.

configure.ac

@@ -98,7 +98,6 @@ AS_CASE([$enable_egl],
     AS_CASE([$host_os],
             [mingw*], [build_egl=no],
             [darwin*], [build_egl=no],
-            [android*], [build_egl=no],
             [build_egl=yes])
   ],
 

meson.build

@@ -60,7 +60,7 @@ if enable_egl == 'auto'
   elif host_system == 'darwin'
     build_egl = false
   elif host_system == 'android'
-    build_egl = false
+    build_egl = true
   else
     build_egl = true
   endif