Fixing several formulae that fail with LLVM

Specifically: emacs, glib, igraph, and zeromq
Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/emacs.rb

@@ -53,6 +53,8 @@ class Emacs <Formula
   end
 
   def install
+    fails_with_llvm "Duplicate symbol errors while linking."
+
     configure_args = [
       "--prefix=#{prefix}",
       "--without-dbus",

Formula/glib.rb

@@ -16,6 +16,8 @@ class Glib <Formula
   depends_on 'gettext'
 
   def install
+    fails_with_llvm "Undefined symbol errors while linking"
+
     # Snow Leopard libiconv doesn't have a 64bit version of the libiconv_open
     # function, which breaks things for us, so we build our own
     # http://www.mail-archive.com/gtk-list@gnome.org/msg28747.html

Formula/igraph.rb

@@ -9,6 +9,8 @@ class Igraph <Formula
   depends_on 'gmp'
 
   def install
+    fails_with_llvm "Segfault while compiling."
+
     system "./configure", "--disable-debug", "--disable-dependency-tracking", "--prefix=#{prefix}"
     system "make install"
   end

Formula/zeromq.rb

@@ -6,6 +6,7 @@ class Zeromq <Formula
   md5 'c9cb3ee4499df1781f8ddc03c20d656b'
 
   def install
+    fails_with_llvm "Compiling with LLVM gives a segfault while linking."
     system "./configure", "--disable-dependency-tracking", "--prefix=#{prefix}"
     system "make install"
   end