Fix for SPACK-35: Fortran not working properly

- Spack needed symlinks in env for fortran compilers.
- 'fc' is a bash bulitin, so can't use it for fortran compiler.
  - switched to 'f90' for this.

- mpich 3 builds with fortran now.
  - enabled shared libs in mpich package

lib/spack/env/cc

@@ -59,7 +59,7 @@ elif command in ('c++', 'CC', 'g++', 'clang++'):
 elif command in ('f77'):
     command = spack_f77
     language = "Fortran 77"
-elif command in ('fc'):
+elif command in ('fc', 'f90', 'f95'):
     command = spack_fc
     language = "Fortran 90"
 elif command in ('ld', 'cpp'):

lib/spack/env/f77

@@ -0,0 +1 @@
+cc

lib/spack/env/f90

@@ -0,0 +1 @@
+cc

lib/spack/env/f95

@@ -0,0 +1 @@
+cc

lib/spack/env/fc

@@ -0,0 +1 @@
+cc

lib/spack/spack/build_environment.py

@@ -90,7 +90,7 @@ def set_compiler_environment_variables(pkg):
     os.environ['CC']  = 'cc'
     os.environ['CXX'] = 'c++'
     os.environ['F77'] = 'f77'
-    os.environ['FC']  = 'fc'
+    os.environ['FC']  = 'f90'
 
     # Set SPACK compiler variables so that our wrapper knows what to call
     if compiler.cc:
@@ -173,6 +173,7 @@ def set_module_variables_for_package(pkg):
         m.std_cmake_args.append('-DCMAKE_FIND_FRAMEWORK=LAST')
 
     # Emulate some shell commands for convenience
+    m.pwd        = os.getcwd
     m.cd         = os.chdir
     m.mkdir      = os.mkdir
     m.makedirs   = os.makedirs

var/spack/packages/mpich/package.py

@@ -38,6 +38,8 @@ class Mpich(Package):
     provides('mpi@:1', when='@1:')
 
     def install(self, spec, prefix):
-        configure("--prefix=" + prefix)
+        configure(
+            "--prefix=" + prefix,
+            "--enable-shared")
         make()
         make("install")