Bug 1520516 - Set verbose logging for cargo when -v is passed to |./mach build|. r=nalexander

Differential Revision: https://phabricator.services.mozilla.com/D16907

--HG--
extra : moz-landing-system : lando

config/rules.mk

@@ -835,11 +835,7 @@ endif
 cargo_build_flags += --manifest-path $(CARGO_FILE)
 ifdef BUILD_VERBOSE_LOG
 cargo_build_flags += -vv
-else
-ifdef MOZ_AUTOMATION
-cargo_build_flags += -vv
-endif # MOZ_AUTOMATION
-endif # BUILD_VERBOSE_LOG
+endif
 
 # Enable color output if original stdout was a TTY and color settings
 # aren't already present. This essentially restores the default behavior

python/mozbuild/mozbuild/base.py

@@ -649,6 +649,8 @@ class MozbuildObject(ProcessExecutionMixin):
 
         if silent:
             args.append('-s')
+        else:
+            args.append('BUILD_VERBOSE_LOG=1')
 
         # Print entering/leaving directory messages. Some consumers look at
         # these to measure progress.