[build] sped up the build considerable.

We used to use the mango SPI processor, but this had two major issues:
* ecj wouldn't run annotation processors, requiring a separate proc:only compile run with javac
* mangoSPI couldn't do incremental compilation, so this required a full rebuild just to generate SPI files, every time.

Addressed by updating to IPP40 which does support explicit annotation processors even for ecj, and
adding our own SPI generating annotation processor to the build which can deal with incrementals.

There are some limits; removing a `@Provides` annotation on an existing type will need a full clean to pick that up, for example.
These limits seem quite exotic, though.

1 files changed, 83 insertions, 0 deletions

diff --git a/src/spiProcessor/lombok/spi/SpiProcessorService.java b/src/spiProcessor/lombok/spi/SpiProcessorService.java
new file mode 100644
index 00000000..be8d5a21
--- /dev/null
+++ b/src/spiProcessor/lombok/spi/SpiProcessorService.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2021 The Project Lombok Authors.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package lombok.spi;
+
+import java.util.Iterator;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
+
+import javax.lang.model.util.Elements;
+
+final class SpiProcessorService {
+	private final String name;
+	private final Set<String> providers = new TreeSet<String>();
+	
+	SpiProcessorService(String name) {
+		if (name == null) throw new NullPointerException("name");
+		this.name = name;
+	}
+	
+	public String getName() {
+		return name;
+	}
+	
+	void addProvider(String className) {
+		if (className == null) throw new NullPointerException("className");
+		providers.add(className);
+	}
+	
+	boolean removeProvider(String provider) {
+		return providers.remove(provider);
+	}
+	
+	String toProvidersListFormat() {
+		return providers.stream().collect(Collectors.joining("\n"));
+	}
+	
+	void addAllFromProvidersNameList(String in) {
+		for (String line : in.split("\\n")) {
+			String[] content = line.split("#", 2);
+			if (content.length == 0) continue;
+			String trimmed = content[0].trim();
+			String[] elems = trimmed.split("\\s+", 2);
+			if (elems.length == 0 || elems[0].isEmpty()) continue;
+			String cn = elems[0];
+			addProvider(cn);
+		}
+	}
+	
+	void stripProvidersWithoutSourceFile(Elements elements) {
+		Iterator<String> it = providers.iterator();
+		while (it.hasNext()) {
+			if (!sourceExists(elements, it.next())) it.remove();
+		}
+	}
+	
+	private boolean sourceExists(Elements elements, String typeName) {
+		return elements.getTypeElement(typeName) != null;
+	}
+	
+	@Override public String toString() {
+		return name + " = " + providers;
+	}
+}