Ensure the APPS environment variable is not set when building OpenSSL

var/spack/packages/openssl/package.py

@@ -17,6 +17,10 @@ class Openssl(Package):
     parallel = False
 
     def install(self, spec, prefix):
+        # OpenSSL uses a variable APPS in its Makefile. If it happens to be set
+        # in the environment, then this will override what is set in the
+        # Makefile, leading to build errors.
+        del env['APPS']
         if spec.satisfies("=darwin-x86_64") or spec.satisfies("=ppc64"):
             # This needs to be done for all 64-bit architectures (except Linux,
             # where it happens automatically?)