Fix Travis to really test 32 bits

To make sure 32 bits arch is being tested, try the following test which should
fail in 32 bits mode:
```go
package utils

import (
	"math/bits"
	"testing"
)

func TestBreak(t *testing.T) {
	if bits.UintSize != 64 {
		panic("bits.UintSize != 64")
	}
}
```

.travis.yml

@@ -4,12 +4,22 @@ language: go
 go:
   - "1.12"
 
+# Travis overrides the GOARCH env var probably in its `travis_setup_go`
+# function, so we need a work around...
 jobs:
   include:
     - name: "Unit Tests 64 bit arch"
-      env: GOARCH="amd64"
+      env:
+        - XGOARCH="amd64"
     - name: "Unit Test 32 bit arch"
-      env: GOARCH="386"
+      env:
+        - XGOARCH="386"
 
 env:
   - GO111MODULE=on
+
+before_install:
+  - export GOARCH=$XGOARCH
+
+script:
+  - go test -v ./...

utils/showarchbits_test.go

@@ -0,0 +1,11 @@
+package utils
+
+import (
+	"fmt"
+	"math/bits"
+	"testing"
+)
+
+func TestShowArchBits(t *testing.T) {
+	fmt.Printf("Architecture is %v bits\n", bits.UintSize)
+}