diff --git a/configure b/configure
index 0448c6b..a0a6989 100755
--- a/configure
+++ b/configure
@@ -2945,6 +2945,7 @@ dragonfly*) template=netbsd ;;
  linux*|gnu*|k*bsd*-gnu)
            template=linux ;;
    mingw*) template=win32 ;;
+    msys*) template=win32 ;;
   netbsd*) template=netbsd ;;
  openbsd*) template=openbsd ;;
  solaris*) template=solaris ;;
diff --git a/configure.in b/configure.in
index 23b5bb8..11be746 100644
--- a/configure.in
+++ b/configure.in
@@ -67,6 +67,7 @@ dragonfly*) template=netbsd ;;
  linux*|gnu*|k*bsd*-gnu)
            template=linux ;;
    mingw*) template=win32 ;;
+    msys*) template=win32 ;;
   netbsd*) template=netbsd ;;
  openbsd*) template=openbsd ;;
  solaris*) template=solaris ;;
diff --git a/src/bin/pg_upgrade/Makefile b/src/bin/pg_upgrade/Makefile
index adb0d5d..8b76650 100644
--- a/src/bin/pg_upgrade/Makefile
+++ b/src/bin/pg_upgrade/Makefile
@@ -37,7 +37,7 @@ clean distclean maintainer-clean:
 	       pg_upgrade_dump_*.custom pg_upgrade_*.log
 
 check: test.sh all
-	MAKE=$(MAKE) bindir=$(bindir) libdir=$(libdir) EXTRA_REGRESS_OPTS="$(EXTRA_REGRESS_OPTS)" $(SHELL) $< --install
+	MAKE=$(MAKE) bindir=$(bindir) libdir=$(libdir) EXTRA_REGRESS_OPTS="$(EXTRA_REGRESS_OPTS)" $(SHELL) HOST_OS=$(host_os) $< --install
 
 # installcheck is not supported because there's no meaningful way to test
 # pg_upgrade against a single already-running server
diff --git a/src/bin/pg_upgrade/test.sh b/src/bin/pg_upgrade/test.sh
index f895663..28f8a2e 100644
--- a/src/bin/pg_upgrade/test.sh
+++ b/src/bin/pg_upgrade/test.sh
@@ -30,11 +30,12 @@ standard_initdb() {
 	../../test/regress/pg_regress --config-auth "$PGDATA"
 }
 
-# Establish how the server will listen for connections
-testhost=`uname -s`
+# Establish how the server will listen for connections.
+# Fall back to uname if necessary
+testhost=${HOST_OS:-$(uname -s)}
 
 case $testhost in
-	MINGW*|MSYS*)
+	MINGW*)
 		LISTEN_ADDRESSES="localhost"
 		PGHOST=localhost
 		;;