termite: Add support for macOS (#43415)

Replace fetchgit with fetchFromGitHub now that it supports fetching
submodules. Remove unnecessary postPatch to add <math.h> as termite
already includes <cmath>. Add a patch to include <errno.h> on all
platforms and remove the --as-needed flag from ld on macOS.

pkgs/applications/misc/termite/add_errno_header.patch

···
+From 95c90f302c384f410dc92e64468ac7061b57fe2d Mon Sep 17 00:00:00 2001
+From: Michael Hoang <[e-mail]>
+Date: Fri, 13 Jul 2018 19:03:09 +1000
+Subject: [PATCH] Add errno.h header which isn't always included automatically.
+
+---
+ termite.cc | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/termite.cc b/termite.cc
+index 160fe82..13e2572 100644
+--- a/termite.cc
++++ b/termite.cc
+@@ -21,6 +21,7 @@
+ #include <cstdlib>
+ #include <cstring>
+ #include <cmath>
++#include <errno.h>
+ #include <functional>
+ #include <limits>
+ #include <map>
+-- 
+2.17.1
+

pkgs/applications/misc/termite/default.nix

···
-{ stdenv, fetchgit, pkgconfig, vte, gtk3, ncurses, makeWrapper, wrapGAppsHook, symlinkJoin
+{ stdenv, fetchFromGitHub, lib, pkgconfig, vte, gtk3, ncurses, makeWrapper, wrapGAppsHook, symlinkJoin
 , configFile ? null
 }:
 
···
   termite = stdenv.mkDerivation {
     name = "termite-${version}";
 
-    src = fetchgit {
-      url = "https://github.com/thestinger/termite";
-      rev = "refs/tags/v${version}";
+    src = fetchFromGitHub {
+      owner = "thestinger";
+      repo = "termite";
+      rev = "v${version}";
       sha256 = "02cn70ygl93ghhkhs3xdxn5b1yadc255v3yp8cmhhyzsv5027hvj";
+      fetchSubmodules = true;
     };
 
     # https://github.com/thestinger/termite/pull/516
-    patches = [ ./url_regexp_trailing.patch ];
-
-    postPatch = "sed '1i#include <math.h>' -i termite.cc";
+    patches = [ ./url_regexp_trailing.patch ./add_errno_header.patch
+                ] ++ lib.optional stdenv.isDarwin ./remove_ldflags_macos.patch;
 
     makeFlags = [ "VERSION=v${version}" "PREFIX=" "DESTDIR=$(out)" ];
 

pkgs/applications/misc/termite/remove_ldflags_macos.patch

···
+From 1b5a6934635c55472eb7949bd87ab3f45fa1b2f3 Mon Sep 17 00:00:00 2001
+From: Michael Hoang <[e-mail]>
+Date: Fri, 13 Jul 2018 19:01:51 +1000
+Subject: [PATCH] Remove --as-needed flag from ld to fix compilation on macOS.
+
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index b115f42..ab301ba 100644
+--- a/Makefile
++++ b/Makefile
+@@ -29,7 +29,7 @@ ifeq (${CXX}, clang++)
+ 	CXXFLAGS += -Wimplicit-fallthrough
+ endif
+ 
+-LDFLAGS := -s -Wl,--as-needed ${LDFLAGS}
++LDFLAGS := -s -Wl ${LDFLAGS}
+ LDLIBS := ${shell pkg-config --libs ${GTK} ${VTE}}
+ 
+ termite: termite.cc url_regex.hh util/clamp.hh util/maybe.hh util/memory.hh
+-- 
+2.17.1
+