Make annotation dependencies optional again.

All static-analaysis-related annotation libraries are
compile-time-only and can therefore be marked optional.

Also changes the Java module descriptors to use 'requires static'
instead of plain 'requires' for the corresponding modules, which lifts
the runtime dependency from the point of view of the module system.

Change-Id: I414907b002f6b0290ddb61b6f0ce899481c6efd3
diff --git a/jgvariant-ostree/src/main/java/module-info.java b/jgvariant-ostree/src/main/java/module-info.java
index 18daf94..cdf65dd 100644
--- a/jgvariant-ostree/src/main/java/module-info.java
+++ b/jgvariant-ostree/src/main/java/module-info.java
@@ -80,10 +80,12 @@
  */
 module eu.mulk.jgvariant.ostree {
   requires transitive eu.mulk.jgvariant.core;
-  requires com.google.errorprone.annotations;
-  requires org.apiguardian.api;
-  requires org.jetbrains.annotations;
+
   requires org.tukaani.xz;
 
+  requires static com.google.errorprone.annotations;
+  requires static org.apiguardian.api;
+  requires static org.jetbrains.annotations;
+
   exports eu.mulk.jgvariant.ostree;
 }