gcc in /mingw64 finds no libs in /msys64/mingw64

It mystifies me why building a PL/Java *shared* object on Windows
requires being able to find a libpostgres.a *static* archive, but
such are the rules that were copied over to the JS build scheme.

What goes wrong if the -L$PKGLIBDIR and -lpostgres just aren't there?

Author: jcflack

pljava-so/pom.xml

@@ -268,7 +268,7 @@ var configuration = [
 				l.addAll(files);
 
 				// From compiler-mingw64 profile
-				l.addAll(of("-L" + pkglibdir, "-Bdynamic", "-lpostgres"));
+				l.addAll(of("-Bdynamic"));
 			});
 			linkingProcess.directory(target_path.toFile());
 			return runWindowsCRuntimeCommand(linkingProcess);