hepmcanalysis: propagate cxxstd from root (#29512)

* Use same cxx value as root

* Remove pointer syntax from non-pointer type in source

* Run patch function before build

* Use raw string in filter_file and merge edit function with patch

* Escape parentheses

* Use gDirectory from ROOT instead of CurrentDirectory function

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

@@ -22,17 +22,14 @@ class Hepmcanalysis(MakefilePackage):
     depends_on('root')
     depends_on('clhep')
 
-    variant('cxxstd',
-            default='11',
-            values=('11', '14', '17'),
-            multi=False,
-            description='Use the specified C++ standard when building.')
-
     patch('lcg.patch')
 
-    def edit(self, spec, prefix):
+    def patch(self):
+        filter_file(r"TDirectory::CurrentDirectory\(\)",
+                    r"gDirectory",
+                    "src/baseAnalysis.cc")
         filter_file(r"CXXFLAGS(.*)", r"CXXFLAGS\1 -std=c++" +
-                    self.spec.variants['cxxstd'].value, "config.mk")
+                    self.spec['root'].variants['cxxstd'].value, "config.mk")
 
     def setup_build_environment(self, env):
         env.set("HepMCdir", self.spec['hepmc'].prefix)