buildMozillaMach: create symbols output

Thie zip bundle in this output is used in the dumps sent by the
crashreporter. For this to happen we need to upload this zip file to
https://symbols.mozilla.org, which is a separate effort.

pkgs/applications/networking/browsers/firefox/common.nix

@@ -23,6 +23,7 @@
 # build time
 , autoconf
 , cargo
+, dump_syms
 , makeWrapper
 , nodejs
 , perl
@@ -168,6 +169,11 @@ buildStdenv.mkDerivation ({
 
   inherit src unpackPhase meta;
 
+  outputs = [
+    "out"
+    "symbols"
+  ];
+
   # Add another configure-build-profiling run before the final configure phase if we build with pgo
   preConfigurePhases = lib.optionals pgoSupport [
     "configurePhase"
@@ -196,6 +202,7 @@ buildStdenv.mkDerivation ({
   nativeBuildInputs = [
     autoconf
     cargo
+    dump_syms
     llvmPackages.llvm # llvm-objdump
     makeWrapper
     nodejs
@@ -408,7 +415,13 @@ buildStdenv.mkDerivation ({
   # tests were disabled in configureFlags
   doCheck = false;
 
+  # Generate build symbols once after the final build
+  # https://firefox-source-docs.mozilla.org/crash-reporting/uploading_symbol.html
   preInstall = ''
+    ./mach buildsymbols
+    mkdir -p $symbols/
+    cp mozobj/dist/*.crashreporter-symbols.zip $symbols/
+
     cd mozobj
   '';