Cannot filter external specs using `reuse:from` about spack HOT 1 CLOSED

diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 0d84c53970..3c8f385a29 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -1649,11 +1649,13 @@ def external_packages(self):
         if isinstance(reuse_yaml, typing.Mapping):
             default_include = reuse_yaml.get("include", [])
             default_exclude = reuse_yaml.get("exclude", [])
+            libc_externals = list(all_libcs())
             for source in reuse_yaml.get("from", []):
                 if source["type"] != "external":
                     continue
 
-                include = source.get("include", default_include)
+                # Since libcs are implicit externals, we need to implicitly include them
+                include = source.get("include", default_include) + libc_externals
                 exclude = source.get("exclude", default_exclude)
                 spec_filters.append(
                     SpecFilter(
diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index 85cc697a2d..60165338c6 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -1424,6 +1424,7 @@ opt_criterion(73, "deprecated versions used").
 #minimize{
     1@73+Priority,PackageNode
     : attr("deprecated", PackageNode, _),
+      not external(PackageNode),
       build_priority(PackageNode, Priority)
 }.