graph-tool 2.80

This also adds support for openmp.

Fix style errors

Formula/g/graph-tool.rb

@@ -3,8 +3,8 @@ class GraphTool < Formula
 
   desc "Efficient network analysis for Python 3"
   homepage "https://graph-tool.skewed.de/"
-  url "https://downloads.skewed.de/graph-tool/graph-tool-2.79.tar.bz2"
-  sha256 "52a254942e75ed3070dea70e692ae101877bbef1009e43ec62fe1806a8de0154"
+  url "https://downloads.skewed.de/graph-tool/graph-tool-2.80.tar.bz2"
+  sha256 "c1a70e075dbe728fad25dc3f5a9a9597880a6d6ff68435b91d21f0b44ef8dbe6"
   license "LGPL-3.0-or-later"
 
   livecheck do
@@ -32,6 +32,8 @@ class GraphTool < Formula
   depends_on "gmp"
   depends_on "google-sparsehash"
   depends_on "gtk+3"
+  depends_on "libomp"
+  depends_on "llvm"
   depends_on macos: :mojave # for C++17
   depends_on "numpy"
   depends_on "pillow"
@@ -134,6 +136,13 @@ def install
     # Linux build is not thread-safe.
     ENV.deparallelize unless OS.mac?
 
+    # Enable openmp
+    if OS.mac?
+      ENV.append_to_cflags "-Xpreprocessor -fopenmp"
+      ENV.append "LDFLAGS", "-L/usr/local/opt/libomp/lib -lomp"
+      ENV.append "CPPFLAGS", "-I/usr/local/opt/libomp/include"
+    end
+
     args = %W[
       PYTHON=#{python}
       --with-python-module-path=#{prefix/site_packages}