[clutter] build: Rework the default rules for the EGL backend

[Emmanuele Bassi <ebassi src gnome org>]

commit fae541ebf1d5ecb41bd439843bcbbec3c8d63fd5
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Dec 11 16:39:32 2015 +0000

    build: Rework the default rules for the EGL backend
    
    So that we can set it to 'check', and do configure-time discovery of the
    dependencies, instead of enabling it explicitly.
    
    This should make it easier to spot build issues on environments like
    Continuous, which build Clutter and Cogl for running as part of the
    display server infrastructure on Wayland.

 configure.ac |  100 ++++++++++++++++++++++++++++------------------------------
 1 files changed, 48 insertions(+), 52 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index e32f5dd..1bc6e67 100644
--- a/configure.ac
+++ b/configure.ac
@@ -263,13 +263,13 @@ AC_ARG_ENABLE([gdk-backend],
               [enable_gdk=$enableval],
               [enable_gdk=check])
 AC_ARG_ENABLE([wayland-backend],
-              [AS_HELP_STRING([--enable-wayland-backend=@<:@yes/no@:>@], [Enable the Wayland client backend 
(default=no)])],
+              [AS_HELP_STRING([--enable-wayland-backend=@<:@yes/no@:>@], [Enable the Wayland client backend 
(default=check)])],
               [enable_wayland=$enableval],
               [enable_wayland=check])
 AC_ARG_ENABLE([egl-backend],
               [AS_HELP_STRING([--enable-egl-backend=@<:@yes/no@:>@], [Enable the EGL framebuffer backend 
(default=no)])],
               [enable_egl=$enableval],
-              [enable_egl=no])
+              [enable_egl=check])
 AC_ARG_ENABLE([mir-backend],
               [AS_HELP_STRING([--enable-mir-backend=@<:@yes/no@:>@], [Enable the Mir client backend 
(default=no)])],
               [enable_mir=$enableval],
@@ -279,26 +279,37 @@ AC_ARG_ENABLE([cex100-backend],
               [enable_cex100=$enableval],
               [enable_cex100=no])
 
+dnl Additional input backends
+AC_ARG_ENABLE([tslib-input],
+              [AS_HELP_STRING([--enable-tslib-input=@<:@yes/no@:>@], [Enable TSLib for input events 
(default=no)])],
+              [enable_tslib=$enableval],
+              [enable_tslib=no])
+AC_ARG_ENABLE([evdev-input],
+              [AS_HELP_STRING([--enable-evdev-input=@<:@yes/no@:>@], [Enable evdev for input events 
(default=check)])],
+              [enable_evdev=$enableval],
+              [enable_evdev=check])
+
 dnl Define default values
-AS_IF([test "x$enable_x11" = "xcheck"],
-      [
-        PKG_CHECK_EXISTS([x11], [enable_x11=yes], [enable_x11=no])
-      ])
+AS_IF([test "x$enable_x11" = xcheck], [
+  PKG_CHECK_EXISTS([x11], [enable_x11=yes], [enable_x11=no])
+])
 
-AS_IF([test "x$enable_win32" = "xcheck"],
-      [
-        AS_IF([test "x$platform_win32" = "xyes"], [enable_win32=yes], [enable_win32=no])
-      ])
+AS_IF([test "x$enable_win32" = xcheck], [
+  AS_IF([test "x$platform_win32" = "xyes"], [enable_win32=yes], [enable_win32=no])
+])
 
-AS_IF([test "x$enable_osx" = "xcheck"],
-      [
-        AS_IF([test "x$platform_quartz" = "xyes"], [enable_osx=yes], [enable_osx=no])
-      ])
+AS_IF([test "x$enable_osx" = xcheck], [
+  AS_IF([test "x$platform_quartz" = "xyes"], [enable_osx=yes], [enable_osx=no])
+])
 
-AS_IF([test "x$enable_gdk" = "xcheck"],
-      [
-        PKG_CHECK_EXISTS([gdk-3.0 >= gdk_req_version], [enable_gdk=yes], [enable_gdk=no])
-      ])
+AS_IF([test "x$enable_gdk" = xcheck], [
+  PKG_CHECK_EXISTS([gdk-3.0 >= gdk_req_version], [enable_gdk=yes], [enable_gdk=no])
+])
+
+AS_IF([test "x$enable_egl" = xcheck], [
+  PKG_CHECK_EXISTS([egl], [enable_egl=yes], [enable_egl=no])
+  PKG_CHECK_EXISTS([libinput], [enable_evdev=yes], [enable_evdev=no])
+])
 
 dnl Per-backend rules
 AS_IF([test "x$enable_x11" = "xyes"],
@@ -525,40 +536,25 @@ AS_IF([test "x$platform_linux" = "xyes"],
         AC_DEFINE([OS_LINUX], [1], [Define to 1 if building for Linux])
       ])
 
-# additional input backends
-
-AC_ARG_ENABLE([tslib-input],
-              [AS_HELP_STRING([--enable-tslib-input=@<:@yes/no@:>@], [Enable TSLib for input events 
(default=no)])],
-              [enable_tslib=$enableval],
-              [enable_tslib=no])
-AC_ARG_ENABLE([evdev-input],
-              [AS_HELP_STRING([--enable-evdev-input=@<:@yes/no@:>@], [Enable evdev for input events 
(default=no)])],
-              [enable_evdev=$enableval],
-              [enable_evdev=no])
-
-AS_IF([test "x$enable_tslib" = "xyes"],
-      [
-        PKG_CHECK_MODULES(TSLIB, [tslib-1.0], [have_tslib=yes], [have_tslib=no])
-        AS_IF([test "x$have_tslib" = "xyes"],
-              [
-                CLUTTER_INPUT_BACKENDS="$CLUTTER_INPUT_BACKENDS tslib"
-                experimental_input_backend="yes"
-                AC_DEFINE([HAVE_TSLIB], [1], [Have tslib for touchscreen handling])
-                SUPPORT_TSLIB=1
-              ])
-      ])
+AS_IF([test "x$enable_tslib" = xyes], [
+  PKG_CHECK_EXISTS([tslib-1.0], [have_tslib=yes], [have_tslib=no])
+  AS_IF([test "x$have_tslib" = xyes], [
+    CLUTTER_INPUT_BACKENDS="$CLUTTER_INPUT_BACKENDS tslib"
+    experimental_input_backend="yes"
+    AC_DEFINE([HAVE_TSLIB], [1], [Have tslib for touchscreen handling])
+    SUPPORT_TSLIB=1
+  ])
+])
 
-AS_IF([test "x$enable_evdev" = "xyes"],
-      [
-        PKG_CHECK_MODULES(EVDEV, [gudev-1.0 xkbcommon], [have_evdev=yes], [have_evdev=no])
-        AS_IF([test "x$have_evdev" = "xyes"],
-              [
-                CLUTTER_INPUT_BACKENDS="$CLUTTER_INPUT_BACKENDS evdev"
-                BACKEND_PC_FILES_PRIVATE="$BACKEND_PC_FILES_PRIVATE libudev >= $LIBUDEV_REQ_VERSION libinput 
> = $LIBINPUT_REQ_VERSION xkbcommon"
-                AC_DEFINE([HAVE_EVDEV], [1], [Have evdev support for input handling])
-                SUPPORT_EVDEV=1
-              ])
-      ])
+AS_IF([test "x$enable_evdev" = xyes], [
+  PKG_CHECK_EXISTS([libinput gudev-1.0 xkbcommon], [have_evdev=yes], [have_evdev=no])
+  AS_IF([test "x$have_evdev" = "xyes"], [
+    CLUTTER_INPUT_BACKENDS="$CLUTTER_INPUT_BACKENDS evdev"
+    BACKEND_PC_FILES_PRIVATE="$BACKEND_PC_FILES_PRIVATE libudev >= $LIBUDEV_REQ_VERSION libinput >= 
$LIBINPUT_REQ_VERSION xkbcommon"
+    AC_DEFINE([HAVE_EVDEV], [1], [Have evdev support for input handling])
+    SUPPORT_EVDEV=1
+  ])
+])
 
 # conditionals for use in automake files...
 AM_CONDITIONAL(SUPPORT_GLX,     [test "x$SUPPORT_GLX" = "x1"])