etc: make the new bash-completion file work for all variants of our executables.

In particular make it also work with the `gimp-console` and with all
symlink names.

Also rename the bash completion file using the full application version
so that it will be possible to install several such completion files
side by side.

etc/bash_completion.in

@@ -1,4 +1,3 @@
-
 __gimp()
 {
     COMPREPLY=()
@@ -73,4 +72,19 @@ __gimp()
    return 0
 }
 
-complete -F __gimp gimp
+complete -F __gimp @GIMP_MAIN_EXE@
+if command -v @GIMP_SYMLINK1@ 2>&1 > /dev/null
+then
+  complete -F __gimp @GIMP_SYMLINK1@
+  complete -F __gimp @GIMP_SYMLINK2@
+fi
+
+if command -v @GIMP_CONSOLE_EXE@ 2>&1 > /dev/null
+then
+  complete -F __gimp @GIMP_CONSOLE_EXE@
+  if command -v @GIMP_CONSOLE_SYMLINK1@ 2>&1 > /dev/null
+  then
+    complete -F __gimp @GIMP_CONSOLE_SYMLINK1@
+    complete -F __gimp @GIMP_CONSOLE_SYMLINK2@
+  fi
+fi

etc/meson.build

@@ -36,8 +36,18 @@ if have_bash
     bash_comp_inst_dir = get_option('datadir') / 'bash-completion' / 'completions'
   endif
 
-  install_data('bash_completion',
-    install_dir: bash_comp_inst_dir,
-    rename: 'gimp',
-  )
+  bash_completion_conf = configuration_data()
+  bash_completion_conf.set('GIMP_MAIN_EXE', gimpmain_exe_name)
+  bash_completion_conf.set('GIMP_SYMLINK1', 'gimp-' + gimp_app_version_major.to_string())
+  bash_completion_conf.set('GIMP_SYMLINK2', 'gimp')
+
+  bash_completion_conf.set('GIMP_CONSOLE_EXE',      gimpconsole_exe_name)
+  bash_completion_conf.set('GIMP_CONSOLE_SYMLINK1', 'gimp-console-' + gimp_app_version_major.to_string())
+  bash_completion_conf.set('GIMP_CONSOLE_SYMLINK2', 'gimp-console')
+
+  configure_file(input : 'bash_completion.in',
+                 output: 'gimp-' + gimp_app_version,
+                 configuration: bash_completion_conf,
+                 install: true,
+                 install_dir: bash_comp_inst_dir)
 endif