netcdf-fortran: enforce autoreconf when building with NAG. (#8844)

* netcdf-fortran: enforce autoreconf when building with NAG.

* netcdf-fortran: patch the configure script instead of running autoreconf to get rid of additional dependencies.

* netcdf-fortran: add comment for the patch.

var/spack/repos/builtin/packages/netcdf-fortran/nag.patch

@@ -0,0 +1,31 @@
+diff --git a/configure b/configure
+index 06ac8b0..d518a1a 100755
+--- a/configure
++++ b/configure
+@@ -10657,6 +10657,8 @@ _LT_EOF
+ 	lf95*)				# Lahey Fortran 8.1
+ 	  whole_archive_flag_spec=
+ 	  tmp_sharedflag='--shared' ;;
++	nagfor*)
++	  tmp_sharedflag='-Wl,-shared' ;;
+ 	xl[cC]* | bgxl[cC]* | mpixl[cC]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+ 	  tmp_sharedflag='-qmkshrobj'
+ 	  tmp_addflag= ;;
+@@ -14252,6 +14254,8 @@ _LT_EOF
+ 	lf95*)				# Lahey Fortran 8.1
+ 	  whole_archive_flag_spec_F77=
+ 	  tmp_sharedflag='--shared' ;;
++	nagfor*)
++	  tmp_sharedflag='-Wl,-shared' ;;
+ 	xl[cC]* | bgxl[cC]* | mpixl[cC]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+ 	  tmp_sharedflag='-qmkshrobj'
+ 	  tmp_addflag= ;;
+@@ -17142,6 +17146,8 @@ _LT_EOF
+ 	lf95*)				# Lahey Fortran 8.1
+ 	  whole_archive_flag_spec_FC=
+ 	  tmp_sharedflag='--shared' ;;
++	nagfor*)
++	  tmp_sharedflag='-Wl,-shared' ;;
+ 	xl[cC]* | bgxl[cC]* | mpixl[cC]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+ 	  tmp_sharedflag='-qmkshrobj'
+ 	  tmp_addflag= ;;

var/spack/repos/builtin/packages/netcdf-fortran/package.py

@@ -36,6 +36,10 @@ class NetcdfFortran(AutotoolsPackage):
 
     depends_on('netcdf')
 
+    # The default libtool.m4 is too old to handle NAG compiler properly:
+    # https://github.com/Unidata/netcdf-fortran/issues/94
+    patch('nag.patch', when='@:4.4.4%nag')
+
     def configure_args(self):
         return ['CPPFLAGS=-I' + self.spec['netcdf'].prefix.include]