Fix JDK-8201553: Update FX build to use gradle 4.8 (#92)

Reviewed-by: @prrace @johanvos @tiainen

build.gradle

@@ -1221,8 +1221,8 @@ if (Integer.parseInt(NUM_COMPILE_THREADS.toString()) < 1) {
     NUM_COMPILE_THREADS = 1
 }
 
-// Check for Gradle 4.3, error if < 3.0.
-if (gradle.gradleVersion != "4.3") {
+// Check for Gradle 4.8, error if < 4.3.
+if (gradle.gradleVersion != "4.8") {
     def ver = gradle.gradleVersion.split("[\\.]");
     def gradleMajor = Integer.parseInt(ver[0]);
     def gradleMinor = Integer.parseInt(ver[1].split("[^0-9]")[0]);
@@ -1237,7 +1237,7 @@ if (gradle.gradleVersion != "4.3") {
 
     logger.warn("*****************************************************************");
     logger.warn("Unsupported gradle version $gradle.gradleVersion in use.");
-    logger.warn("Only version 4.3 is supported. Use this version at your own risk");
+    logger.warn("Only version 4.8 is supported. Use this version at your own risk");
     if ( err != "") logger.warn(err);
     logger.warn("*****************************************************************");
 }

gradle/legal/gradle.md

@@ -1,4 +1,4 @@
-## Gradle v4.3
+## Gradle v4.8
 
 ### Apache 2.0 License
 <pre>

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.8-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists