Bug 1477792 - Save the rust-analysis on macOS searchfox builds. r=emilio

This is the equivalent of bug 1432475 but for macOS.

MozReview-Commit-ID: DT8V9Vd9eLS

--HG--
extra : rebase_source : 982e2fcb8aed0640acd80025319fdcac24634c47

browser/config/mozconfigs/macosx64/debug-searchfox

@@ -7,6 +7,10 @@ MOZ_AUTOMATION_L10N_CHECK=0
 ac_add_options --enable-debug
 ac_add_options --enable-dmd
 
+# Save rust analysis (this requires unlocking the unstable features)
+export RUSTC_BOOTSTRAP=1
+export RUSTFLAGS="-Zsave-analysis"
+
 ac_add_options --enable-clang-plugin
 ac_add_options --enable-mozsearch-plugin