Bring back OSGi support (#351)

it was accidentally dropped when switching from Maven to Gradle.

Also include Git Commit SHA again in MANIFEST 'Implementation-Build' attribute.

build.gradle

@@ -10,6 +10,7 @@ plugins {
  id 'com.github.hexomod.macro.preprocessor' version '0.9'
  id 'me.champeau.jmh' version '0.7.0' apply false
  id 'checkstyle'
+ id 'org.ajoberstar.grgit' version '5.2.2'
 }
 repositories {
  mavenCentral()
@@ -23,7 +24,7 @@ if (buildProfile == 'experimental') {
 }
 
 group 'org.joml'
-version '1.10.7'
+version '1.10.8-SNAPSHOT'
 
 configurations {
  buildhelper
@@ -86,6 +87,23 @@ if (buildProfile == 'default') {
  compileJava.finalizedBy(java6to2, moduleInfoGenerator)
 }
 
+jar {
+ manifest {
+ attributes(
+ 'Created-By': 'Gradle',
+ 'Implementation-Title': 'JOML',
+ 'Implementation-Version': version,
+ 'Implementation-Vendor': 'JOML',
+ 'Bundle-ManifestVersion': '2',
+ 'Bundle-Name': 'JOML',
+ 'Bundle-SymbolicName': 'org.joml',
+ 'Bundle-Version': version,
+ 'Export-Package': 'org.joml,org.joml.sampling',
+ 'Implementation-Build': grgit.head().id,
+ )
+ }
+}
+
 nexusPublishing {
  repositories {
  sonatype()