Rename gc => bdw-gc, fix libunistring bug

var/spack/repos/builtin/packages/bdw-gc/package.py

@@ -25,7 +25,7 @@
 from spack import *
 
 
-class Gc(Package):
+class BdwGc(Package):
     """The Boehm-Demers-Weiser conservative garbage collector is a garbage
     collecting replacement for C malloc or C++ new."""
 

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

@@ -41,7 +41,7 @@ class Guile(Package):
     depends_on('gettext')
     depends_on('libtool@1.5.6:')
     depends_on('libunistring@0.9.3:')
-    depends_on('gc@7.0:')
+    depends_on('bdw-gc@7.0:')
     depends_on('libffi')
     depends_on('readline', when='+readline')
     depends_on('pkg-config')

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

@@ -34,11 +34,9 @@ class Libunistring(Package):
 
     version('0.9.6', 'cb09c398020c27edac10ca590e9e9ef3')
 
-    depends_on('libiconv')
-
     def install(self, spec, prefix):
-        configure('--prefix={0}'.format(prefix),
-                  '--with-libiconv-prefix={0}'.format(spec['libiconv'].prefix))
+        configure('--prefix={0}'.format(prefix))
 
         make()
+        # make('check')  # test-verify fails for me, contacted developers
         make('install')