diff --git a/index/li/libgmp/libgmp-external.toml b/index/li/libgmp/libgmp-external.toml
index 14235fe2..3b6bd5cb 100644
--- a/index/li/libgmp/libgmp-external.toml
+++ b/index/li/libgmp/libgmp-external.toml
@@ -15,3 +15,7 @@ msys2 = ["mingw-w64-x86_64-gmp"]
 kind = "version-output"
 version-command = [ "pkg-config", "--modversion", "gmp" ]
 version-regexp = "([\\d\\.]+)"
+
+# pkg-config requires further steps to make packages findable by
+# dependencies that Alire does not yet support
+available = false
diff --git a/index/li/libgnutls/libgnutls-external.toml b/index/li/libgnutls/libgnutls-external.toml
index 923c7a81..4cbf1922 100644
--- a/index/li/libgnutls/libgnutls-external.toml
+++ b/index/li/libgnutls/libgnutls-external.toml
@@ -14,3 +14,7 @@ kind = "system"
 kind = "version-output"
 version-command = [ "pkg-config", "--modversion", "gnutls" ]
 version-regexp = "([\\d\\.]+)"
+
+# pkg-config requires further steps to make packages findable by
+# dependencies that Alire does not yet support
+available = false
\ No newline at end of file
diff --git a/index/li/libgtk3/libgtk3-external.toml b/index/li/libgtk3/libgtk3-external.toml
index 51fde6aa..1d3f20c2 100644
--- a/index/li/libgtk3/libgtk3-external.toml
+++ b/index/li/libgtk3/libgtk3-external.toml
@@ -16,3 +16,6 @@ msys2 = ["mingw-w64-x86_64-gtk3"]
 kind = "version-output"
 version-command = [ "pkg-config", "--modversion", "gtk+-3.0" ]
 version-regexp = "([\\d\\.]+)"
+# pkg-config requires further steps to make packages findable by
+# dependencies that Alire does not yet support
+available = false