Prevent that another processor (such as xindy) is used when set in prefs.
xindy does not play well with hyperref.
Fixes #11708
\default_output_format pdf2
\output_sync 0
\bibtex_command default
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format pdf2
\output_sync 0
\bibtex_command default
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format default
\output_sync 0
\bibtex_command bibtex
-\index_command default
+\index_command makeindex
\float_placement class
\float_alignment class
\paperfontsize 12
\default_output_format pdf2
\output_sync 0
\bibtex_command default
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format pdf2
\output_sync 0
\bibtex_command default
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format pdf2
\output_sync 0
\bibtex_command default
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format pdf2
\output_sync 0
\bibtex_command bibtex
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true
\default_output_format pdf2
\output_sync 0
\bibtex_command bibtex
-\index_command default
+\index_command makeindex
\paperfontsize 12
\spacing single
\use_hyperref true