Armadillo: fix for linker error with apple-clang 15 (#44551)

* Armadillo needs to use -ld_classic with apple-clang 15

var/spack/repos/builtin/packages/armadillo/package.py

@@ -42,6 +42,14 @@ class Armadillo(CMakePackage):
     # platform's compiler is adding `#define linux 1`.
     patch("undef_linux.patch", when="platform=linux")
 
+    def flag_handler(self, name, flags):
+        spec = self.spec
+        if name == "ldflags":
+            if spec.satisfies("%apple-clang@15:"):
+                flags.append("-Wl,-ld_classic")
+
+        return (flags, None, None)
+
     def patch(self):
         # Do not include Find{BLAS_type} because we are specifying the
         # BLAS/LAPACK libraries explicitly.