Azure: Add 'tools-only' build for macOS X hosts

Add building the 'tools-only' target on macOS X 'Catalina'.  Hopefully
this will catch changes to host tools that are incompatible on BSD style
environments.

Signed-off-by: Tom Rini <trini@konsulko.com>

.azure-pipelines.yml

@@ -1,6 +1,7 @@
 variables:
   windows_vm: vs2017-win2016
   ubuntu_vm: ubuntu-18.04
+  macos_vm: macOS-10.15
   ci_runner_image: trini/u-boot-gitlab-ci-runner:bionic-20200403-27Apr2020
   # Add '-u 0' options for Azure pipelines, otherwise we get "permission
   # denied" error when it tries to "useradd -m -u 1001 vsts_azpcontainer",
@@ -44,6 +45,20 @@ jobs:
           # Tell MSYS2 not to ‘cd’ our startup directory to HOME
           CHERE_INVOKING: yes
 
+  - job: tools_only_macOS
+    displayName: 'Ensure host tools build for macOS X'
+    pool:
+      vmImage: $(macos_vm)
+    steps:
+      - script: brew install make
+        displayName: Brew install dependencies
+      - script: |
+          gmake tools-only_config tools-only NO_SDL=1 \
+            HOSTCFLAGS="-I/usr/local/opt/openssl@1.1/include" \
+            HOSTLDFLAGS="-L/usr/local/opt/openssl@1.1/lib" \
+            -j$(sysctl -n hw.logicalcpu)
+        displayName: 'Perform tools-only build'
+
   - job: cppcheck
     displayName: 'Static code analysis with cppcheck'
     pool: