fix(dev): fix detection of container tool in make

Fixes the following error when `ENVIRONMENT=true` and neither Docker or Podman are available:

    make: podman: No such file or directory
    make: *** [Makefile:174: build] Error 127

Podman was being used as fallback even if also not available.
A descriptive error is now reported instead in this situation.

Signed-off-by: Hugo Hromic <hhromic@gmail.com>

Makefile

@@ -34,7 +34,13 @@ export VERBOSE ?= false
 # Override the container tool. Tries docker first and then tries podman.
 export CONTAINER_TOOL ?= auto
 ifeq ($(CONTAINER_TOOL),auto)
-	override CONTAINER_TOOL = $(shell docker version >/dev/null 2>&1 && echo docker || echo podman)
+	ifeq ($(shell docker version >/dev/null 2>&1 && echo docker), docker)
+		override CONTAINER_TOOL = docker
+	else ifeq ($(shell podman version >/dev/null 2>&1 && echo podman), podman)
+		override CONTAINER_TOOL = podman
+	else
+		override CONTAINER_TOOL = unknown
+	endif
 endif
 # If we're using podman create pods else if we're using docker create networks.
 export CURRENT_DIR = $(shell pwd)
@@ -108,6 +114,9 @@ endif
 
 # We use a volume here as non-Linux hosts are extremely slow to share disks, and Linux hosts tend to get permissions clobbered.
 define ENVIRONMENT_EXEC
+	ifeq $($(CONTAINER_TOOL), unknown)
+		$(error "Please install a container tool such as Docker or Podman")
+	endif
 	${ENVIRONMENT_PREPARE}
 	@echo "Entering environment..."
 	@mkdir -p target