Description: multithreaded compiler hangs on multiple files (approx > 20)
 Set "useSingleThread = true" by default
 Note that you need prebuilt eclipse-ecj.jar with this patch applied.
Bug-GCC: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=34574
Bug-GCC: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51615
Index: ecj-3.10.1/src/org.eclipse.jdt.core/org/eclipse/jdt/internal/compiler/batch/Main.java
===================================================================
--- ecj-3.10.1.orig/src/org.eclipse.jdt.core/org/eclipse/jdt/internal/compiler/batch/Main.java
+++ ecj-3.10.1/src/org.eclipse.jdt.core/org/eclipse/jdt/internal/compiler/batch/Main.java
@@ -4106,7 +4106,7 @@ public void performCompilation() {
 	this.batchCompiler.remainingIterations = this.maxRepetition-this.currentRepetition/*remaining iterations including this one*/;
 	// temporary code to allow the compiler to revert to a single thread
 	String setting = System.getProperty("jdt.compiler.useSingleThread"); //$NON-NLS-1$
-	this.batchCompiler.useSingleThread = setting != null && setting.equals("true"); //$NON-NLS-1$
+	this.batchCompiler.useSingleThread = setting == null || setting.equals("true"); //$NON-NLS-1$
 
 	if (this.compilerOptions.complianceLevel >= ClassFileConstants.JDK1_6
 			&& this.compilerOptions.processAnnotations) {