Speed up fast compiles config (#433)

optionally make "fast build" config 40% faster on mac by removing some debug info

.cargo/config_fast_builds

@@ -14,4 +14,9 @@ rustflags = ["-C", "link-arg=-fuse-ld=/usr/local/bin/zld", "-Zshare-generics=y"]
 
 [target.x86_64-pc-windows-msvc]
 linker = "rust-lld.exe"
-rustflags = ["-Zshare-generics=y"]
+rustflags = ["-Zshare-generics=y"]
+
+# Optional: Uncommenting the following improves compile times, but reduces the amount of debug info to 'line number tables only'
+# In most cases the gains are negligible, but if you are on macos and have slow compile times you should see significant gains.
+#[profile.dev]
+#debug = 1