Use pdflatex explicitely. Otherwise we get

make[6]: Entering directory '/home/rene/graphite2/build/doc/doxygen/latex'
rm -f *.ps *.dvi *.aux *.toc *.idx *.ind *.ilg *.log *.out *.brf *.blg *.bbl refman.pdf
xelatex refman
This is XeTeX, Version 3.141592653-2.6-0.999995 (TeX Live 2023/Debian) (preloaded format=xelatex)
 restricted \write18 enabled.
entering extended mode
(./refman.tex
LaTeX2e <2023-11-01>
L3 programming layer <2023-11-09>
! Undefined control sequence.
l.4   \pdfminorversion
                      =7
? 
! Emergency stop.
l.4 
    
No pages of output.
Transcript written on refman.log.
make[6]: *** [Makefile:12: refman.pdf] Error 1

diff --git a/doc/full.cfg b/doc/full.cfg
index d3d864a..88bab69 100644
--- a/doc/full.cfg
+++ b/doc/full.cfg
@@ -1099,7 +1099,7 @@ LATEX_OUTPUT           = latex
 # generating bitmaps for formulas in the HTML output, but not in the
 # Makefile that is written to the output directory.
 
-LATEX_CMD_NAME         = xelatex
+LATEX_CMD_NAME         = pdflatex
 
 # The MAKEINDEX_CMD_NAME tag can be used to specify the command name to
 # generate index for LaTeX. If left blank `makeindex' will be used as the
diff --git a/doc/public.cfg b/doc/public.cfg
index 90a0c33..3c887e4 100644
--- a/doc/public.cfg
+++ b/doc/public.cfg
@@ -1099,7 +1099,7 @@ LATEX_OUTPUT           = latex
 # generating bitmaps for formulas in the HTML output, but not in the
 # Makefile that is written to the output directory.
 
-LATEX_CMD_NAME         = xelatex
+LATEX_CMD_NAME         = pdflatex
 
 # The MAKEINDEX_CMD_NAME tag can be used to specify the command name to
 # generate index for LaTeX. If left blank `makeindex' will be used as the