diff --git a/index/xm/xmlada/xmlada-21.0.0.toml b/index/xm/xmlada/xmlada-21.0.0.toml
index b9937aa1..13464b52 100644
--- a/index/xm/xmlada/xmlada-21.0.0.toml
+++ b/index/xm/xmlada/xmlada-21.0.0.toml
@@ -13,10 +13,17 @@ project-files = ["distrib/xmlada.gpr",
                  "schema/xmlada_schema.gpr",
                  "unicode/xmlada_unicode.gpr"]
 
-[[actions]]
+# XMLada 21.0 config scripts are not able to detect build machine on msys2.
+# We explicitly set the value in on the command line:
+[[actions."case(distribution)".msys2]]
 type = "post-fetch"
 command = ["sh", "configure", "--build=x86_64-w64-mingw32"]
 
+# For other hosts the detection works fine:
+[[actions."case(distribution)"."..."]]
+type = "post-fetch"
+command = ["sh", "configure"]
+
 [gpr-externals]
 LIBRARY_TYPE = ["static", "relocatable", "static-pic"]
 XMLADA_BUILD_MODE = ["distrib", "Debug", "Production",
diff --git a/index/xm/xmlada/xmlada-22.0.0.toml b/index/xm/xmlada/xmlada-22.0.0.toml
index da001f8f..9e0f8bb9 100644
--- a/index/xm/xmlada/xmlada-22.0.0.toml
+++ b/index/xm/xmlada/xmlada-22.0.0.toml
@@ -21,12 +21,12 @@ disabled = true
 
 # XMLada 22.0 config scripts are not able to detect build machine on msys2.
 # We explicitly set the value in on the command line:
-[[actions."case(os)".windows]]
+[[actions."case(distribution)".msys2]]
 type = "post-fetch"
 command = ["sh", "configure", "--build=x86_64-w64-mingw32"]
 
 # For other hosts the detection works fine:
-[[actions."case(os)"."..."]]
+[[actions."case(distribution)"."..."]]
 type = "post-fetch"
 command = ["sh", "configure"]