Added skipArm flag to disable the arm build entirely

Change-Id: I49c6cb3bfb3b1eda60d5b99b634b1e82fb2afcc8

README.md

@@ -24,6 +24,12 @@ To build just the Native or ARM version, you must access the approriate subproje
 ./gradlew :native:build # Builds just the native version of ntcore
 ```
 
+If you do not have the arm toolchain installed on your computer, you will run into build issues. To disable the arm platform entirely, run with the flag `-PskipArm`, and it will be entirely skipped.
+
+```bash
+./gradlew build -PskipArm # Builds native, disables the arm project
+```
+
 The native version of ntcore will run tests on build. The arm version will not, as the current platform likely does not allow running of an ARM binary.
 
 ## Testing

build.gradle

@@ -7,6 +7,8 @@ if (!hasProperty('repo')) {
     }
 }
 
+ext.buildArm = !project.hasProperty('skipArm')
+
 if (hasProperty('makeDesktop')) {
     println 'Making desktop classifier jar. NOTE: This desktop version should only be used for local testing.' +
             'It will only support the current platform, and will override fetching the latest development version from' +
@@ -161,19 +163,21 @@ def ntcoreZipTask = { project ->
     }
 }
 
-project(':arm') {
-    apply plugin: 'cpp'
+if (buildArm) {
+    project(':arm') {
+        apply plugin: 'cpp'
 
-    ext.buildPlatform = 'arm'
-    ext.isArm = true
+        ext.buildPlatform = 'arm'
+        ext.isArm = true
 
-    apply from: '../toolchains/arm.gradle'
-    if (includeJava) {
-        apply from: '../java/java.gradle'
+        apply from: '../toolchains/arm.gradle'
+        if (includeJava) {
+            apply from: '../java/java.gradle'
+        }
+
+        setupModel(project, true)
+        ntcoreZipTask(project)
     }
-
-    setupModel(project, true)
-    ntcoreZipTask(project)
 }
 
 project(':native') {

publish.gradle

@@ -7,13 +7,14 @@ apply plugin: 'maven-publish'
 publishing {
     publications {
         def nat = project('native')
-        def arm = project('arm')
         if (!project.hasProperty('skipJava')) {
             java(MavenPublication) {
                 artifact nat.jar
-                artifact arm.jar
                 artifact nat.networktablesJavaSource
                 artifact nat.networktablesJavadoc
+                if (project.buildArm) {
+                    artifact project('arm').jar
+                }
 
                 if (project.hasProperty('makeDesktop')) {
                     artifact nat.jar, {
@@ -28,8 +29,10 @@ publishing {
         }
         cpp(MavenPublication) {
             artifact nat.ntcoreZip
-            artifact arm.ntcoreZip
             artifact ntcoreSourceZip
+            if (project.buildArm) {
+                artifact project(':arm').ntcoreZip
+            }
 
             if (project.hasProperty('makeDesktop')) {
                 artifact nat.ntcoreZip, {

settings.gradle

@@ -1 +1,5 @@
-include 'arm', 'native', 'gmock'
+include 'native', 'gmock'
+
+if (!hasProperty('skipArm')) {
+    include 'arm'
+}