diff --git a/build/makefile_base.mak b/build/makefile_base.mak
index e44f079d..1d4a9aaa 100644
--- a/build/makefile_base.mak
+++ b/build/makefile_base.mak
@@ -59,6 +59,10 @@ endif
 export CC
 export CXX
 
+# If set below, we're invoking some build steps in a container that requires sudo -- will test sudo and show a warning
+# at build start.
+USING_SUDO_CONTAINER :=
+
 # Selected container mode shell
 DOCKER_SHELL_BASE = sudo docker run --rm --init -v $(HOME):$(HOME) -w $(CURDIR) -e HOME=$(HOME) \
                                     -v /etc/passwd:/etc/passwd:ro -u $(shell id -u):$(shell id -g) -h $(shell hostname) \
@@ -69,12 +73,14 @@ DOCKER_SHELL_BASE = sudo docker run --rm --init -v $(HOME):$(HOME) -w $(CURDIR)
 ifeq ($(STEAMRT64_MODE),docker)
 	SELECT_DOCKER_IMAGE := $(STEAMRT64_IMAGE)
 	CONTAINER_SHELL64 := $(DOCKER_SHELL_BASE)
+	USING_SUDO_CONTAINER := 1
 else ifneq ($(STEAMRT64_MODE),)
 	foo := $(error Unrecognized STEAMRT64_MODE $(STEAMRT64_MODE))
 endif
 ifeq ($(STEAMRT32_MODE),docker)
 	SELECT_DOCKER_IMAGE := $(STEAMRT32_IMAGE)
 	CONTAINER_SHELL32 := $(DOCKER_SHELL_BASE)
+	USING_SUDO_CONTAINER := 1
 else ifneq ($(STEAMRT32_MODE),)
 	foo := $(error Unrecognized STEAMRT32_MODE $(STEAMRT32_MODE))
 endif
@@ -96,15 +102,28 @@ ifndef CONTAINER_SHELL32
 	CONTAINER_SHELL32 := $(SHELL)
 endif
 
-$(info Testing configured 64bit container)
-ifneq ($(shell $(CONTAINER_SHELL64) -c "echo hi"), hi)
-$(error "Cannot run commands in 64bit container")
+# Using a sudo container? Make sure we have sudo and show warning
+ifeq ($(USING_SUDO_CONTAINER),1)
+$(info :: NOTE: Some build steps will run in a container, which invokes sudo automatically)
+$(info ::       If building in parallel (-j) this can result in sudo prompts buried in the output)
+$(info :: Testing sudo access now)
+ifneq ($(shell sudo echo hi),hi)
+$(error Failed to invoke sudo)
 endif
-$(info Testing configured 32bit container)
-ifneq ($(shell $(CONTAINER_SHELL32) -c "echo hi"), hi)
-$(error "Cannot run commands in 32bit container")
 endif
 
+# Helper to test
+.PHONY: test-container test-container32 test-container64
+test-container: test-container64 test-container32
+
+test-container64:
+	@echo >&2 ":: Testing 64-bit container"
+	$(CONTAINER_SHELL64) -c "echo Hello World!"
+
+test-container32:
+	@echo >&2 ":: Testing 32-bit container"
+	$(CONTAINER_SHELL32) -c "echo Hello World!"
+
 # Many of the configure steps below depend on the makefile itself, such that they are dirtied by changing the recipes
 # that create them.  This can be annoying when working on the makefile, building with NO_MAKEFILE_DEPENDENCY=1 disables
 # this.