diff --git a/check/check-define-variable b/check/check-define-variable
index bf8aebe..d35e445 100755
--- a/check/check-define-variable
+++ b/check/check-define-variable
@@ -9,7 +9,15 @@ set -e
 
 . ${srcdir}/common
 
-ARGS="--define-variable=includedir=/includedir/ --cflags simple"
+case ${MACHTYPE} in
+*-msys)
+    # Make sure path doesn't get mangled on MSYS
+    ARGS="--define-variable=includedir=\\/includedir/ --cflags simple"
+    ;;
+*)
+    ARGS="--define-variable=includedir=/includedir/ --cflags simple"
+    ;;
+esac
 RESULT="-I/includedir/"
 
 run_test