[LyX/master] Create the other side of conversion chain when IM is banned (bug #12646).

[Pavel Sanda]

commit 179c0d6ff25de361d801f5e4a58564d6e8e29c67
Author: Pavel Sanda <sanda at lyx.org>
Date:   Fri Jul 21 23:17:55 2023 +0200

    Create the other side of conversion chain when IM is banned (bug #12646).
    
    We allow png, jpg to channel through already existing tiff2ps (library
    libtiff-tools). Other formats can be added if there is a request.
    
    For future reference:
    - using pnmtops seem to have issues with landscape/portrait flip, so
      tiff2ps seems better alternative.
    - using GraphicsMagick won't help because some distros ban postscript
      processing directly in its code (e.g. openSUSE)
    
    This patch finishes IM policy ban handling, we can't probably do much
    better.
---
 lib/configure.py |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/configure.py b/lib/configure.py
index 7a5052f..e5f71f7 100644
--- a/lib/configure.py
+++ b/lib/configure.py
@@ -1206,8 +1206,10 @@ def checkConverterEntries():
         except:
             removeFiles(['mock.eps'])
             #needs empty record otherwise default converter will be issued
-            rc_entry = r'\converter eps        png        ""	""'
-            addToRC(rc_entry)
+            addToRC(r'''\converter eps        png        ""	""
+\converter png        eps        ""	""
+\converter jpg        tiff        "convert $$i $$o"	""
+\converter png        tiff        "convert $$i $$o"	""''')
             logger.info('ImageMagick seems to ban conversions from EPS. Disabling direct EPS->PNG.')
     #
     # no agr -> pdf6 converter, since the pdf library used by gracebat is not