[gegl] bin: avoid linking to symbols that wont exist without mrg

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 984bd75bca656984e12c42ddf61dae795efa5e91
Author: Øyvind Kolås <pippin gimp org>
Date:   Wed Jan 16 17:36:54 2019 +0100

    bin: avoid linking to symbols that wont exist without mrg

 bin/Makefile.am |  1 +
 bin/argvs.c     | 11 +++++++++++
 2 files changed, 12 insertions(+)
---
diff --git a/bin/Makefile.am b/bin/Makefile.am
index 6af9322cf..0cbe2f704 100644
--- a/bin/Makefile.am
+++ b/bin/Makefile.am
@@ -4,6 +4,7 @@ endif
 
 AM_CPPFLAGS = \
        -I$(top_srcdir) \
+       -I$(top_srcdir)/bin \
        -I$(top_builddir)/bin \
        -I$(top_builddir)/gegl \
        -I$(top_srcdir)/gegl \
diff --git a/bin/argvs.c b/bin/argvs.c
index 73d8c9fc8..ae4f8e1b0 100644
--- a/bin/argvs.c
+++ b/bin/argvs.c
@@ -122,7 +122,18 @@ argvs_cleanup (void)
     argvs_free (e);
 }
 
+#if HAVE_MRG
 #include "argvs-commands.inc"
+#else
+int cmd_echo_on (COMMAND_ARGS);
+int cmd_source (COMMAND_ARGS);
+int cmd_argvs (COMMAND_ARGS);
+int cmd_aa_help (COMMAND_ARGS);
+
+/* dummy to keep things working even without argvs when no ui is built */
+void argvs_register(void) {
+}
+#endif
 /* cmds.inc is supposed to be created by your build system by using the
  * following shell-script to run with your .c files as argument for
  * collecting command definitions.