-# to make doc pdf
-# needs texlive a jour (done on machines lgls for x86_64-linux)
-# https://www.tug.org/texlive/quickinstall.html
+# to make doc pdf without error
+# user needs texlive up-to-date
+# see https://www.tug.org/texlive/quickinstall.html
+
+# on machines Centos7 dm2s/lgls as x86_64-linux his is not good,
+# see https://www.centos.org/forums/viewtopic.php?t=54410
+# so user simply have to set PATH on one correct texlive package
+# compiled here: