[gdm] Add --disable-fallback-greeter configure option

[Colin Walters <walters src gnome org>]

commit acc931c762b5510103a7f49cf3074c1228700cb8
Author: Colin Walters <walters verbum org>
Date:   Thu Mar 7 17:57:55 2013 -0500

    Add --disable-fallback-greeter configure option
    
    See https://bugzilla.gnome.org/show_bug.cgi?id=672943
    
    This pairs with the above commit; it allows operating system
    builders to entirely disable the fallback greeter, and rely
    on software GL.
    
    At the moment we keep this a configure option since some consumers of
    GDM are using the fallback greeter.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=695414

 configure.ac                            |    5 +++++
 data/Makefile.am                        |   13 ++++++++++---
 data/gdm-shell-with-fallback.session.in |    5 +++++
 data/gdm-shell.session.in               |    2 --
 4 files changed, 20 insertions(+), 5 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 14b6ff3..fce9287 100644
--- a/configure.ac
+++ b/configure.ac
@@ -291,6 +291,11 @@ AC_ARG_WITH(plymouth,
             AS_HELP_STRING([--with-plymouth],
                            [Add plymouth support @<:@default=auto@:>@]),
             [with_plymouth=$withval], [with_plymouth=auto])
+AC_ARG_ENABLE(fallback-greeter,
+             AS_HELP_STRING([--enable-fallback-greeter],
+                             [Enable fallback greeter @<:@default=no@:>@]),,
+              enable_fallback_greeter=no)
+AM_CONDITIONAL(ENABLE_FALLBACK_GREETER, test x$enable_fallback_greeter = xyes)
 
 AC_ARG_WITH(at-spi-registryd-directory,
             AS_HELP_STRING([--with-at-spi-registryd-directory],
diff --git a/data/Makefile.am b/data/Makefile.am
index f85b578..3d7bf3b 100644
--- a/data/Makefile.am
+++ b/data/Makefile.am
@@ -80,10 +80,18 @@ gdm.schemas.in: $(srcdir)/gdm.schemas.in.in
                -e 's,[ ]sbindir[@],$(sbindir),g' \
                <$(srcdir)/gdm.schemas.in.in >gdm.schemas.in
 
-gdm-shell.session: $(srcdir)/gdm-shell.session.in
+if ENABLE_FALLBACK_GREETER
+FALLBACK_SESSION_IN = $(srcdir)/gdm-shell-with-fallback.session.in
+else
+FALLBACK_SESSION_IN = $(srcdir)/gdm-shell.session.in
+endif
+
+EXTRA_DIST += gdm-shell.session.in gdm-shell-with-fallback.session.in
+
+gdm-shell.session: $(FALLBACK_SESSION_IN)
        sed     -e 's,[ ]libexecdir[@],$(libexecdir),g' \
                -e 's,[ ]CHECK_ACCELERATED_DIR[@],$(CHECK_ACCELERATED_DIR),g' \
-               < $(srcdir)/gdm-shell.session.in > gdm-shell.session
+               < $< > $  tmp && mv $  tmp $@
 
 localealiasdir = $(datadir)/gdm
 localealias_DATA = locale.alias
@@ -153,7 +161,6 @@ EXTRA_DIST +=                       \
        PreSession.in           \
        PostSession.in          \
        PostLogin               \
-       gdm-shell.session.in    \
        dconf-profile \
        00-upstream-settings \
        00-upstream-settings-locks \
diff --git a/data/gdm-shell-with-fallback.session.in b/data/gdm-shell-with-fallback.session.in
new file mode 100644
index 0000000..1bea43c
--- /dev/null
+++ b/data/gdm-shell-with-fallback.session.in
@@ -0,0 +1,5 @@
+[GNOME Session]
+Name=Display Manager
+RequiredComponents=gnome-shell;gnome-settings-daemon;
+IsRunnableHelper=bash -c 'type -p gnome-shell >& /dev/null && 
@CHECK_ACCELERATED_DIR@/gnome-session-check-accelerated'
+FallbackSession=gdm-fallback
diff --git a/data/gdm-shell.session.in b/data/gdm-shell.session.in
index 1bea43c..585c45d 100644
--- a/data/gdm-shell.session.in
+++ b/data/gdm-shell.session.in
@@ -1,5 +1,3 @@
 [GNOME Session]
 Name=Display Manager
 RequiredComponents=gnome-shell;gnome-settings-daemon;
-IsRunnableHelper=bash -c 'type -p gnome-shell >& /dev/null && 
@CHECK_ACCELERATED_DIR@/gnome-session-check-accelerated'
-FallbackSession=gdm-fallback