Replace dejavu with xorg font alias misc

To have the library working on with minimum font dependency on multiple
distribution, we use xorg font alias misc.
Font available are listed here:
Debian based: /etc/X11/fonts/misc/xfonts-base-alias
Arch based: /usr/share/fonts/misc/fonts.alias

Xdraw.c

@@ -31,8 +31,8 @@
 		  char_size: erreur
 		. sol: definir une font par defaut dans InitX par une
 		       appel a char_size(12).
-   - A. Lescourt oct 2017: change la font pour dejavu, (helvetica n'étant plus
-        . présent sur la plupart des distributation linux par defaut)
+   - A. Lescourt oct 2017: change la font helvetica par les xorg font alias misc
+          pour fonctionner avec X11 de base sur de multiple distribution
 
   procedure POLYGONE(P : in Type_Point;
                      N : in Integer);
@@ -266,33 +266,27 @@ int size;
   Font fonte;
 
   if (size == 8) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-80-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "5x8");
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
   else if (size == 10) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-100-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "6x10");
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
   else if (size == 12) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-120-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "6x12");
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
   else if (size == 14) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-140-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "7x14");
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
   else if (size == 18) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-180-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "10x20");  // no size 18 available in xorg font alias misc
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
   else if (size == 24) {
-    font_struct = XLoadQueryFont(canal_aff,
-            "-*-dejavu sans mono-medium-r-normal--*-240-*-*-*-*-iso10646-1");
+    font_struct = XLoadQueryFont(canal_aff, "12x24");
     XSetFont(canal_aff,contx_graph,font_struct->fid);
   }
 }