Realised that -r8 option needs to be in mkmf template file for double…

… precision, but should not be there for single precision. Do not currently have a dynamic way of editing that mkmf template file, so added feature to choose different mkmf template file for single precision. Format is just same name as current mkmf template file with _simple added at the end.

src/extra/python/isca/codebase.py

@@ -121,6 +121,7 @@ def __init__(self, repo=None, commit=None, directory=None, storedir=P(GFDL_WORK,
         self.path_names = []
         self.compile_flags = []  # users can append to this to add additional compiler options
         self.precision_compile_flags = ['-DOVERLOAD_C8'] #Default is to use double precision. User can change to single precision using cb.use_single_precision() before compile step 
+        self.env_suffix = ''
 
     @property
     def code_is_available(self):
@@ -271,7 +272,7 @@ def compile(self, debug=False, optimisation=None):
             'srcdir': self.srcdir,
             'workdir': self.workdir,
             'compile_flags': compile_flags_str,
-            'env_source': env,
+            'env_source': env+self.env_suffix,
             'path_names': path_names_str,
             'executable_name': self.executable_name,
             'run_idb': debug,
@@ -289,6 +290,7 @@ def use_single_precision(self):
             self.precision_compile_flags = ['-DOVERLOAD_C4', '-DOVERLOAD_R4']
             self.executable_name = self.executable_name.strip('.x')+'_single.x'
             self.builddir = P(self.workdir, 'build', self.executable_name.split('.')[0])
+            self.env_suffix = '_single' #needs a seperate env file as flags are different