config error if you pass --enable-wayland-only or --enable-wayland-clients without wayland required packages to avoid later build fail

Summary:
You can get build error if you don't have required packages for wayland configuration such as pixman-1.
I think it would be good to know you about package error at configuration time.

Test Plan:
1. change your name of pixman-1.pc file temporarily.
2. also change your name of pixman.h file temporarily.
3. config e with --enable-wayland-clients option
4. make

Reviewers: raster, devilhorns, zmike

CC: cedric, stefan_schmidt

Differential Revision: https://phab.enlightenment.org/D782

configure.ac

@@ -832,8 +832,7 @@ if test "x${e_cv_want_wayland_only}" != "xno" || test "x${e_cv_want_wayland_clie
     [
       have_wayland=yes
       AC_DEFINE_UNQUOTED([HAVE_WAYLAND],[1],[enable wayland support])
-    ],
-    [have_wayland=no])
+    ])
 else
   have_wayland=no
 fi