Don't try to generate documentation when cross-compiling

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@53231 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/Make/Multi.make

@@ -15,7 +15,11 @@ multi: progs htmlmulti
 
 progs: $(PROGFILES)
 
+ifdef CROSS_COMPILING
+htmlmulti:
+else
 htmlmulti: $(HTMLFILES) $(MANFILES)
+endif
 
 $(BIN)/%$(EXE): $(DEPENDENCIES)
 	$(call linker)