openexr: Add custom libs property (#42274)

Libraries for openexr are named libOpenEXR*.so, etc., so the default libs
handler in spec does not find them.

Add a custom libs property to address this.

Partial fix for #42273

Co-authored-by: payerle <payerle@users.noreply.github.com>

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

@@ -85,6 +85,17 @@ class Openexr(CMakePackage, AutotoolsPackage):
     with when("build_system=cmake"):
         depends_on("cmake@3.12:", type="build")
 
+    @property
+    def libs(self):
+        # Override because libs have different case than Spack package name
+        name = "libOpenEXR*"
+        # We expect libraries to be in either lib64 or lib directory
+        for root in (self.prefix.lib64, self.prefix.lib):
+            liblist = find_libraries(name, root=root, shared=True, recursive=False)
+            if liblist:
+                break
+        return liblist
+
 
 class CMakeBuilder(CMakeBuilder):
     def cmake_args(self):