Move maven-compiler-plugin config to properties

This makes it easier to override only the source or target versions (by
overriding maven.compiler.source or maven.compiler.target, respectively)
without needing to introduce a <build> section in the downstream POM.

Author: ctrueden

pom.xml

@@ -157,11 +157,20 @@
 		<!-- Extra maven-surefire-plugin args. -->
 		<scijava.surefire.args />
 
-		<!-- Target version of the Java platform. -->
+		<!-- Compiler configuration. -->
 		<scijava.jvm.version>1.8</scijava.jvm.version>
 		<scijava.jvm.test.version>${scijava.jvm.version}</scijava.jvm.test.version>
 		<!-- NB: 1.8.0_101 is needed for SciJava Maven repository HTTPS support. -->
 		<scijava.jvm.build.version>[1.8.0-101,1.8.9999]</scijava.jvm.build.version>
+		<maven.compiler.source>${scijava.jvm.version}</maven.compiler.source>
+		<maven.compiler.target>${scijava.jvm.version}</maven.compiler.target>
+		<maven.compiler.testSource>${scijava.jvm.test.version}</maven.compiler.testSource>
+		<maven.compiler.testTarget>${scijava.jvm.test.version}</maven.compiler.testTarget>
+		<!--
+		Workaround for a bug in maven-compiler-plugin.
+		See https://issues.apache.org/jira/browse/MCOMPILER-209
+		-->
+		<maven.compiler.useIncrementalCompilation>false</maven.compiler.useIncrementalCompilation>
 
 		<!-- Minimum required Maven version to build the project. -->
 		<scijava.mvn.version>3.3.9</scijava.mvn.version>
@@ -275,17 +284,6 @@
 				<plugin>
 					<artifactId>maven-compiler-plugin</artifactId>
 					<version>${maven-compiler-plugin.version}</version>
-					<configuration>
-						<source>${scijava.jvm.version}</source>
-						<target>${scijava.jvm.version}</target>
-						<testSource>${scijava.jvm.test.version}</testSource>
-						<testTarget>${scijava.jvm.test.version}</testTarget>
-						<!--
-						Workaround for a bug in maven-compiler-plugin.
-						See https://issues.apache.org/jira/browse/MCOMPILER-209
-						-->
-						<useIncrementalCompilation>false</useIncrementalCompilation>
-					</configuration>
 				</plugin>
 
 				<plugin>
@@ -1811,20 +1809,6 @@
 					</plugins>
 				</pluginManagement>
 				<plugins>
-					<!--
-					HACK - Tell Eclipse to use the TEST source and target JVM version.
-					This is necessary because the JVM version used for tests may be newer
-					than that used for the main artifact. Maven is OK with this, but
-					Eclipse wants only a single JVM version for both main and tests.
-					See: https://gist.github.com/aslakknutsen/9648594#gistcomment-1588906
-					-->
-					<plugin>
-						<artifactId>maven-compiler-plugin</artifactId>
-						<configuration>
-							<source>${scijava.jvm.test.version}</source>
-							<target>${scijava.jvm.test.version}</target>
-						</configuration>
-					</plugin>
 					<plugin>
 						<groupId>org.scijava</groupId>
 						<artifactId>scijava-maven-plugin</artifactId>
@@ -1839,6 +1823,17 @@
 					</plugin>
 				</plugins>
 			</build>
+			<properties>
+				<!--
+				HACK - Tell Eclipse to use the TEST source and target JVM version.
+				This is necessary because the JVM version used for tests may be newer
+				than that used for the main artifact. Maven is OK with this, but
+				Eclipse wants only a single JVM version for both main and tests.
+				See: https://gist.github.com/aslakknutsen/9648594#gistcomment-1588906
+				-->
+				<maven.compiler.source>${scijava.jvm.test.version}</maven.compiler.source>
+				<maven.compiler.target>${scijava.jvm.test.version}</maven.compiler.target>
+			</properties>
 		</profile>
 
 		<!--