diff --git a/src/Pure/Admin/build_spass.scala b/src/Pure/Admin/build_spass.scala
--- a/src/Pure/Admin/build_spass.scala
+++ b/src/Pure/Admin/build_spass.scala
@@ -1,175 +1,182 @@
 /*  Title:      Pure/Admin/build_spass.scala
     Author:     Makarius
 
 Build Isabelle SPASS component from unofficial download.
 */
 
 package isabelle
 
 
 object Build_SPASS
 {
   /* build SPASS */
 
   val default_download_url = "https://www.cs.vu.nl/~jbe248/spass-3.8ds-src.tar.gz"
   val standard_version = "3.8ds"
 
   def build_spass(
     download_url: String = default_download_url,
     verbose: Boolean = false,
     progress: Progress = new Progress,
     target_dir: Path = Path.current)
   {
     Isabelle_System.with_tmp_dir("build")(tmp_dir =>
     {
       /* required commands */
 
       List("bison", "flex").foreach(cmd =>
         if (!Isabelle_System.bash(cmd + " --version").ok) error("Missing command: " + cmd))
 
 
       /* component */
 
       val Archive_Name = """^.*?([^/]+)$""".r
       val Component_Name = """^(.+)-src\.tar.gz$""".r
       val Version = """^[^-]+-([^-]+)$""".r
 
       val (archive_name, archive_base_name) =
         download_url match {
           case Archive_Name(name) => (name, Library.perhaps_unsuffix(".tar.gz", name))
           case _ => error("Failed to determine source archive name from " + quote(download_url))
         }
 
       val component_name =
         archive_name match {
           case Component_Name(name) => name
           case _ => error("Failed to determine component name from " + quote(archive_name))
         }
 
       val version =
         component_name match {
           case Version(version) => version
           case _ => error("Failed to determine component version from " + quote(component_name))
         }
 
       if (version != standard_version) {
         progress.echo_warning("Odd SPASS version " + version + " (expected " + standard_version + ")")
       }
 
       val component_dir = Isabelle_System.new_directory(target_dir + Path.basic(component_name))
       progress.echo("Component " + component_dir)
 
       val platform_name =
         proper_string(Isabelle_System.getenv("ISABELLE_PLATFORM64"))
           .getOrElse(error("No 64bit platform"))
 
       val platform_dir = Isabelle_System.make_directory(component_dir + Path.basic(platform_name))
 
 
       /* download source */
 
       val archive_path = tmp_dir + Path.basic(archive_name)
       Isabelle_System.download(download_url, archive_path, progress = progress)
 
       Isabelle_System.bash("tar xzf " + archive_path, cwd = tmp_dir.file).check
       Isabelle_System.bash(
         "tar xzf " + archive_path + " && mv " + Bash.string(archive_base_name) + " src",
         cwd = component_dir.file).check
 
 
       /* build */
 
       progress.echo("Building SPASS ...")
 
       val build_dir = tmp_dir + Path.basic(archive_base_name)
+
+      if (Platform.is_windows) {
+        File.change(build_dir + Path.basic("misc.c"),
+          _.replace("""#include "execinfo.h" """, "")
+           .replaceAll("""void misc_DumpCore\(void\)[^}]+}""", "void misc_DumpCore(void) { abort(); }"))
+      }
+
       Isabelle_System.bash("make",
         cwd = build_dir.file,
         progress_stdout = progress.echo_if(verbose, _),
         progress_stderr = progress.echo_if(verbose, _)).check
 
 
       /* install */
 
       File.copy(build_dir + Path.basic("LICENCE"), component_dir + Path.basic("LICENSE"))
 
       val install_files = List("SPASS")
       for (name <- install_files ::: install_files.map(_ + ".exe")) {
         val path = build_dir + Path.basic(name)
         if (path.is_file) File.copy(path, platform_dir)
       }
 
 
       /* settings */
 
       val etc_dir = Isabelle_System.make_directory(component_dir + Path.basic("etc"))
       File.write(etc_dir + Path.basic("settings"),
         """# -*- shell-script -*- :mode=shellscript:
 
 SPASS_HOME="$COMPONENT/$ISABELLE_PLATFORM64"
 SPASS_VERSION=""" + quote(version) + """
 """)
 
       /* README */
 
       File.write(component_dir + Path.basic("README"),
 """This distribution of SPASS 3.8ds, described in Blanchette, Popescu, Wand, and
 Weidenbach's ITP 2012 paper "More SPASS with Isabelle", has been compiled from
 sources available at """ + download_url + """
 via "make".
 
 The Windows/Cygwin compilation required commenting out the line
 
     #include "execinfo.h"
 
 in "misc.c" as well as most of the body of the "misc_DumpCore" function.
 
 The latest official SPASS sources can be downloaded from
 http://www.spass-prover.org/. Be aware, however, that the official SPASS
 releases are not compatible with Isabelle.
 
 
 Viel SPASS!
 
 
     Jasmin Blanchette
     16-May-2018
 
     Makarius
     """ + Date.Format.date(Date.now()) + "\n")
     })
 }
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool =
     Isabelle_Tool("build_spass", "build prover component from source distribution",
     args =>
     {
       var target_dir = Path.current
       var download_url = default_download_url
       var verbose = false
 
       val getopts = Getopts("""
 Usage: isabelle build_spass [OPTIONS]
 
   Options are:
     -D DIR       target directory (default ".")
     -U URL       download URL
                  (default: """" + default_download_url + """")
     -v           verbose
 
   Build prover component from the specified source distribution.
 """,
         "D:" -> (arg => target_dir = Path.explode(arg)),
         "U:" -> (arg => download_url = arg),
         "v" -> (_ => verbose = true))
 
       val more_args = getopts(args)
       if (more_args.nonEmpty) getopts.usage()
 
       val progress = new Console_Progress()
 
       build_spass(download_url = download_url, verbose = verbose, progress = progress,
         target_dir = target_dir)
     })
 }