--- a/debian/patches/reproducible-build.patch	1969-12-31 21:00:00.000000000 -0300
--- b/debian/patches/reproducible-build.patch	2019-07-15 09:24:48.818456297 -0300
@@ -0,0 +1,24 @@
+Description: Make the build reproducible
+Author: Chris Lamb <lamby@debian.org>
+Last-Update: 2019-07-15
+
+--- ninja-build-1.9.0.orig/src/ninja.cc
++++ ninja-build-1.9.0/src/ninja.cc
+@@ -211,7 +211,7 @@ void Usage(const BuildConfig& config) {
+ "  -C DIR   change to DIR before doing anything else\n"
+ "  -f FILE  specify input build file [default=build.ninja]\n"
+ "\n"
+-"  -j N     run N jobs in parallel (0 means infinity) [default=%d on this system]\n"
++"  -j N     run N jobs in parallel (0 means infinity) [default=#CPUs]\n"
+ "  -k N     keep going until N jobs fail (0 means infinity) [default=1]\n"
+ "  -l N     do not start new jobs if the load average is greater than N\n"
+ "  -n       dry run (don't run commands but act like they succeeded)\n"
+@@ -220,7 +220,7 @@ void Usage(const BuildConfig& config) {
+ "  -t TOOL  run a subtool (use '-t list' to list subtools)\n"
+ "    terminates toplevel options; further flags are passed to the tool\n"
+ "  -w FLAG  adjust warnings (use '-w list' to list warnings)\n",
+-          kNinjaVersion, config.parallelism);
++          kNinjaVersion);
+ }
+ 
+ /// Choose a default value for the -j (parallelism) flag.
--- a/debian/patches/series	1969-12-31 21:00:00.000000000 -0300
--- b/debian/patches/series	2019-07-15 09:24:47.482498635 -0300
@@ -0,0 +1 @@
+reproducible-build.patch