- rework .gitignore

.gitignore

@@ -1,17 +1,25 @@
-build-generic-pc
+#
-build_tmp
+# exclude directories explicitly
-ccache
+#
-cross
+/build-generic-pc
-deps
+/build_tmp
-download
+/cross
-host
+/deps
-internal
+/download
-root
+/host
-static
+/internal
-source
+/local
-local
+/root
-staging
+/source
-config.local
+/staging
-Makefile.local
+/static
-.ignore
+#
+# exclude files explicitly
+#
+/config.local
+/Makefile.local
+#
+# exclude filemasks
+#
 *~
+.ignore