From dd2ad61a93ed8c9e6a7043fc80ef8a91860996a4 Mon Sep 17 00:00:00 2001
From: danielnachun <daniel.nachun@gmail.com>
Date: Sun, 26 Jun 2022 11:03:06 -0700
Subject: [PATCH] nu: fix build on Linux

---
 Formula/nu.rb | 54 +++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/Formula/nu.rb b/Formula/nu.rb
index a5af909dec540..1b786ddd72ba2 100644
--- a/Formula/nu.rb
+++ b/Formula/nu.rb
@@ -15,9 +15,45 @@ class Nu < Formula
 
   depends_on "pcre"
 
+  uses_from_macos "llvm" => [:build, :test]
+  uses_from_macos "swift" => :build # For libdispatch on Linux.
+  uses_from_macos "libffi"
+
+  on_linux do
+    depends_on "gnustep-make" => :build
+    depends_on "gnustep-base"
+    depends_on "libobjc2"
+  end
+
+  # Clang must be used on Linux because GCC Objective-C support is insufficient.
+  fails_with :gcc
+
   def install
     ENV.delete("SDKROOT") if MacOS.version < :sierra
     ENV["PREFIX"] = prefix
+    # Don't hard code path to clang.
+    inreplace "tools/nuke", "/usr/bin/clang", ENV.cc
+
+    unless OS.mac?
+      ENV.append_path "PATH", Formula["gnustep-make"].libexec
+
+      # Help linker find libdispatch from swift on Linux.
+      # This is only used for the mininush temporary compiler and is not needed for nush.
+      ldflags = %W[
+        "-L#{Formula["swift"].libexec}/lib/swift/linux"
+        "-Wl,-rpath,#{Formula["swift"].libexec}/lib/swift/linux"
+      ]
+      ENV["LIBDIRS"] = ldflags.join(" ")
+
+      # Remove unused prefix from ffi.h
+      inreplace ["objc/NuBridge.h", "objc/NuBridge.m", "objc/Nu.m"], "x86_64-linux-gnu/", ""
+
+      # Remove CFLAGS that force using GNU runtime on Linux.
+      # Remove this workaround when upstream drops these flags or provides a way to disable them.
+      # Reported upstream here: https://github.com/programming-nu/nu/issues/99.
+      inreplace "Nukefile", "-DGNU_RUNTIME=1", ""
+      inreplace "Nukefile", "-fgnu-runtime", ""
+    end
 
     inreplace "Nukefile" do |s|
       s.gsub!('(SH "sudo ', '(SH "') # don't use sudo to install
@@ -36,14 +72,16 @@ def install
   end
 
   def caveats
-    <<~EOS
-      Nu.framework was installed to:
-        #{frameworks}/Nu.framework
-
-      You may want to symlink this Framework to a standard macOS location,
-      such as:
-        ln -s "#{frameworks}/Nu.framework" /Library/Frameworks
-    EOS
+    on_macos do
+      <<~EOS
+        Nu.framework was installed to:
+          #{frameworks}/Nu.framework
+
+        You may want to symlink this Framework to a standard macOS location,
+        such as:
+          ln -s "#{frameworks}/Nu.framework" /Library/Frameworks
+      EOS
+    end
   end
 
   test do