add icon-nwp spack package to use a variant: LMU

Now, use a variant +lmu to download from LMU mirrors
Otherwise use the original dkrz git repo

spack_repo/packages/icon-nwp/package.py

@@ -13,12 +13,10 @@ class IconNwp(Package):
     Recipe to build ICON-NWP using the LMU gitlab repository.
     """
 
+    git = "ssh://git@gitlab.dkrz.de/icon/icon-nwp.git"
     homepage = "https://code.mpimet.mpg.de/projects/iconpublic"
     # maintainers("oriol.tinto")
 
-    # Main repository (pointing to LMU's gitlab)
-    git = "ssh://git@gitlab.physik.uni-muenchen.de/w2w/icon.git"
-
     # Version w2w-B6 points to a different repository and branch)
     version("w2w-B6", git="ssh://git@gitlab.physik.uni-muenchen.de/w2w/icon-w2w.git", branch="icon-w2w/icon-nwp-B6")
     # FIXME: The ugly configuration system in older icon versions prevents us from using this package with it.
@@ -28,6 +26,8 @@ class IconNwp(Package):
     version("master", branch="master")
     version("psp", branch="icon-nwp/icon-nwp-psp")
 
+    variant("lmu", default=False, description="if git.url and submodules should be patched to use the LMU mirrors")
+
     # Dependencies
     depends_on("mpi")
     depends_on("netcdf-c")
@@ -48,7 +48,19 @@ class IconNwp(Package):
 
     phases = ["configure", "build", "install"]
 
+    def do_fetch(self, mirror_only=False):
+        if "+lmu" in self.spec:
+            self.fetcher[0].url = self.git = "ssh://git@gitlab.physik.uni-muenchen.de/w2w/icon.git"
+        super(IconNwp, self).do_fetch(mirror_only)
+
     def patch(self):
+        # Run git submodule update
+        git = which("git")
+        if "+lmu" in self.spec:
+            self.patch_submodules()
+        git("submodule", "update", "--init", "--recursive")
+
+    def patch_submodules(self):
         """
         Because of the lack of access rights to the original submodule repositories,
         we patch the gitmodules file to point to a different mirror.
@@ -118,12 +130,7 @@ class IconNwp(Package):
         with git_submodules_file.open("w") as out_f:
             out_f.write(git_modules_patch)
 
-        # Run git submodule update
-        git = which("git")
-        git("submodule", "update", "--init", "--recursive")
-
     def setup_build_environment(self, env):
-
         spec = self.spec
 
         # Some environment variables to set
@@ -137,7 +144,7 @@ class IconNwp(Package):
 
     def configure(self, spec, prefix):
         spec = self.spec
-        print(spec['mpi'].mpifc)
+        print(spec["mpi"].mpifc)
 
         libs = [
             f"-L{spec['netcdf-c'].prefix.lib} -lnetcdf ",  # netcdf-c libs
@@ -202,7 +209,13 @@ class IconNwp(Package):
         rsync("-av", "data/", f"{prefix}/data")
         rsync("-av", "run/", f"{prefix}/run")
         rsync("-av", "--include='*.pdf'", "--exclude='*.*'", "doc/", f"{prefix}/doc/")
-        curl("https://code.mpimet.mpg.de/attachments/download/19568/ICON_tutorial_2019.pdf", "--output",
-             f"{prefix}/doc/ICON_tutorial_2019.pdf")
-        curl("http://www.cosmo-model.org/content/model/documentation/core/emvorado_userguide.pdf", "--output",
-             f"{prefix}/doc/emvorado_userguide.pdf")
+        curl(
+            "https://code.mpimet.mpg.de/attachments/download/19568/ICON_tutorial_2019.pdf",
+            "--output",
+            f"{prefix}/doc/ICON_tutorial_2019.pdf",
+        )
+        curl(
+            "http://www.cosmo-model.org/content/model/documentation/core/emvorado_userguide.pdf",
+            "--output",
+            f"{prefix}/doc/emvorado_userguide.pdf",
+        )