Avoid make install trying to write to folders in /usr.

diff -u -r ../cmatrix-1.2/Makefile.in ./Makefile.in
--- ../cmatrix-1.2/Makefile.in	2017-06-23 11:51:59.000000000 +0200
+++ ./Makefile.in	2017-07-16 19:01:37.496306273 +0200
@@ -760,7 +760,7 @@
 
 info-am:
 
-install-data-am: install-data-local install-man
+install-data-am: install-man
 
 install-dvi: install-dvi-am