podio: ensure Python.h is found in ROOT ACLiC (spack#2602)

* podio: ensure Python.h is found in ROOT ACLiC

* podio: use headers.directories[0] to get str, not list

Author: wdconinc

repos/spack_repo/builtin/packages/podio/package.py

@@ -127,6 +127,10 @@ def setup_run_environment(self, env: EnvironmentModifications) -> None:
         # Frame header needs to be available for python bindings
         env.prepend_path("ROOT_INCLUDE_PATH", self.prefix.include)
 
+        # Pythonizations require Python.h accessible for ACLiC
+        if self.spec.satisfies("@1.5:"):
+            env.prepend_path("ROOT_INCLUDE_PATH", self.spec["python"].headers.directories[0])
+
     def setup_dependent_build_environment(
         self, env: EnvironmentModifications, dependent_spec: Spec
     ) -> None: