Avoid LD_LIBRARY_PATH in pynn-brainscales&hxtorch

We encountered build fails on some HPC sites due to openssl mismatches
between bare-metal tools and spack — especially curl and similar tools
for fetching.
Our build tool, waf, needs to find spack-provided libraries, e.g.
libclang.so, at runtime… so we will only set the environment variable
for this.

packages/hxtorch/package.py

@@ -2,9 +2,10 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import os
+
 from spack import *
 from spack.pkg.builtin.boost import Boost
-import os
 
 
 class Hxtorch(WafPackage):
@@ -128,7 +129,7 @@ class Hxtorch(WafPackage):
         env.set('C_INCLUDE_PATH', ':'.join(include))
         env.set('CPLUS_INCLUDE_PATH', ':'.join(include))
         env.set('LIBRARY_PATH', ':'.join(library))
-        env.set('LD_LIBRARY_PATH', ':'.join(library))
+        env.set('WAF_CONFIGURE_LD_LIBRARY_PATH', ':'.join(library))
         env.prepend_path('PATH', ':'.join(path))
 
     def setup_run_environment(self, env):
@@ -164,6 +165,8 @@ class Hxtorch(WafPackage):
         args = ['--prefix={0}'.format(self.prefix)]
         args += self.configure_args()
 
+        env = os.environ
+        env['LD_LIBRARY_PATH'] = env.get('WAF_CONFIGURE_LD_LIBRARY_PATH')
         self.waf('configure', '--build-profile=release', *args)
 
     def build_args(self):

packages/pynn-brainscales/package.py

@@ -2,6 +2,8 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import os
+
 from spack import *
 from spack.pkg.builtin.boost import Boost
 
@@ -94,7 +96,7 @@ class PynnBrainscales(WafPackage):
         env.set('C_INCLUDE_PATH', ':'.join(include))
         env.set('CPLUS_INCLUDE_PATH', ':'.join(include))
         env.set('LIBRARY_PATH', ':'.join(library))
-        env.set('LD_LIBRARY_PATH', ':'.join(library))
+        env.set('WAF_CONFIGURE_LD_LIBRARY_PATH', ':'.join(library))
         env.prepend_path('PATH', ':'.join(path))
 
     def setup_run_environment(self, env):
@@ -130,6 +132,8 @@ class PynnBrainscales(WafPackage):
         args = ['--prefix={0}'.format(self.prefix)]
         args += self.configure_args()
 
+        env = os.environ
+        env['LD_LIBRARY_PATH'] = env.get('WAF_CONFIGURE_LD_LIBRARY_PATH')
         self.waf('configure', '--build-profile=release', *args)
 
     def build_args(self):