patch 8.1.0222: errors are reported for "make install"

Problem:    Errors are reported for "make install".
Solution:   Skip missing language files. (Christian Brabandt, closes #3254)
diff --git a/src/installman.sh b/src/installman.sh
index a2f09ad..23fc325 100755
--- a/src/installman.sh
+++ b/src/installman.sh
@@ -48,41 +48,49 @@
 
 if test $what = "install"; then
    # vim.1
-   echo installing $destdir/$exename.1
-   LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
-	   -e s+$vimloc/doc+$helpsubloc+ \
-	   -e s+$vimloc/print+$printsubloc+ \
-	   -e s+$vimloc/syntax+$synsubloc+ \
-	   -e s+$vimloc/tutor+$tutorsubloc+ \
-	   -e s+$vimloc/vimrc+$vimrcloc/vimrc+ \
-	   -e s+$vimloc/gvimrc+$vimrcloc/gvimrc+ \
-	   -e s+$vimloc/menu.vim+$scriptloc/menu.vim+ \
-	   -e s+$vimloc/bugreport.vim+$scriptloc/bugreport.vim+ \
-	   -e s+$vimloc/filetype.vim+$scriptloc/filetype.vim+ \
-	   -e s+$vimloc/scripts.vim+$scriptloc/scripts.vim+ \
-	   -e s+$vimloc/optwin.vim+$scriptloc/optwin.vim+ \
-	   -e 's+$vimloc/\*.ps+$scriptloc/\*.ps+' \
-	   $helpsource/vim$langadd.1 > $destdir/$exename.1
-   chmod $manmod $destdir/$exename.1
+   if test -r $helpsource/vim$langadd.1; then
+      echo installing $destdir/$exename.1
+      LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
+	      -e s+$vimloc/doc+$helpsubloc+ \
+	      -e s+$vimloc/print+$printsubloc+ \
+	      -e s+$vimloc/syntax+$synsubloc+ \
+	      -e s+$vimloc/tutor+$tutorsubloc+ \
+	      -e s+$vimloc/vimrc+$vimrcloc/vimrc+ \
+	      -e s+$vimloc/gvimrc+$vimrcloc/gvimrc+ \
+	      -e s+$vimloc/menu.vim+$scriptloc/menu.vim+ \
+	      -e s+$vimloc/bugreport.vim+$scriptloc/bugreport.vim+ \
+	      -e s+$vimloc/filetype.vim+$scriptloc/filetype.vim+ \
+	      -e s+$vimloc/scripts.vim+$scriptloc/scripts.vim+ \
+	      -e s+$vimloc/optwin.vim+$scriptloc/optwin.vim+ \
+	      -e 's+$vimloc/\*.ps+$scriptloc/\*.ps+' \
+	      $helpsource/vim$langadd.1 > $destdir/$exename.1
+      chmod $manmod $destdir/$exename.1
+   fi
 
    # vimtutor.1
-   echo installing $destdir/$exename""tutor.1
-   LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
-	   -e s+$vimloc/tutor+$tutorsubloc+ \
-	   $helpsource/vimtutor$langadd.1 > $destdir/$exename""tutor.1
-   chmod $manmod $destdir/$exename""tutor.1
+   if test -r $helpsource/vimtutor$langadd.1; then
+      echo installing $destdir/$exename""tutor.1
+      LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
+	      -e s+$vimloc/tutor+$tutorsubloc+ \
+	      $helpsource/vimtutor$langadd.1 > $destdir/$exename""tutor.1
+      chmod $manmod $destdir/$exename""tutor.1
+   fi
 
    # vimdiff.1
-   echo installing $destdir/$vimdiffname.1
-   cp $helpsource/vimdiff$langadd.1 $destdir/$vimdiffname.1
-   chmod $manmod $destdir/$vimdiffname.1
+   if test -r $helpsource/vimdiff$langadd.1; then
+      echo installing $destdir/$vimdiffname.1
+      cp $helpsource/vimdiff$langadd.1 $destdir/$vimdiffname.1
+      chmod $manmod $destdir/$vimdiffname.1
+   fi
 
    # evim.1
-   echo installing $destdir/$evimname.1
-   LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
-	   -e s+$vimloc/evim.vim+$scriptloc/evim.vim+ \
-	   $helpsource/evim$langadd.1 > $destdir/$evimname.1
-   chmod $manmod $destdir/$evimname.1
+   if test -r $helpsource/evim$langadd.1; then
+      echo installing $destdir/$evimname.1
+      LC_ALL=C sed -e s+/usr/local/lib/vim+$vimloc+ \
+	      -e s+$vimloc/evim.vim+$scriptloc/evim.vim+ \
+	      $helpsource/evim$langadd.1 > $destdir/$evimname.1
+      chmod $manmod $destdir/$evimname.1
+   fi
 fi
 
 if test $what = "uninstall"; then
@@ -105,7 +113,7 @@
    fi
 fi
 
-if test $what = "xxd"; then
+if test $what = "xxd" -a -r "$helpsource/xxd${langadd}.1"; then
    echo installing $destdir/xxd.1
    cp $helpsource/xxd$langadd.1 $destdir/xxd.1
    chmod $manmod $destdir/xxd.1