btanks: fix build on linux

[LordGrimmauld]

commit 7aeac03 (PR #386495) dropped libX11 and libGLU from propagatedBuildInputs in SDL_compat, and #389106 pointed SDL to SDL_compat, which broke this build

Hydra fail: https://hydra.nixos.org/build/292729441

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

---

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[LordGrimmauld]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 390986

---

x86_64-linux

✅ 1 package built:

• btanks

[grimmauld-bot]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 390986

---

aarch64-linux

✅ 1 package built:

• btanks

[JohnRTitor]

nixpkgs-review result

Generated using nixpkgs-review-gha

Command: nixpkgs-review pr 390986

Logs: https://github.com/JohnRTitor/nixpkgs-review-gha/actions/runs/13930804118

---

x86_64-linux

✅ 1 package built:

• btanks

---

aarch64-linux

✅ 1 package built:

• btanks

---

x86_64-darwin

❌ 1 package failed to build:

• btanks

---

aarch64-darwin

❌ 1 package failed to build:

• btanks

[drupol]

Broken on Darwin ?

[LordGrimmauld]

checking whether the C compiler works... no

Huh? What is going on here? And i am also fairly certain the SDL changes did not cause this specific darwin break.

[JohnRTitor]

configure: error: in '/nix/var/nix-build-smpeg-0.4.5.drv-0/source':
2025-03-18T18:33:55.3170400Z smpeg> configure: error: C compiler cannot create executables

@emilazy

[reckenrode]

I have a fix for smpeg in #391118, but btanks requires non-trivial work to build on Darwin. This is where I got before I decided it wasn’t worth the effort.

1. Apply the following patch, which abuses code injections to fix SCons. The configure check is failing to find SDL because the signature it’s using for main is wrong. It needs to be int main(int argc, char* argv) not void main(void);
2. Set CXXFLAGS to -std=c++03 -x objective-c++; and
3. Make X11 conditional on not-Darwin, and remove whatever is trying to link librt, which doesn’t exist on Darwin.

diff -ur a/SConstruct b/SConstruct
--- a/SConstruct	2025-03-18 19:31:49.308650714 -0400
+++ b/SConstruct	2025-03-18 19:31:32.077240927 -0400
@@ -129,7 +129,7 @@
 	conf.env.Append(LINKFLAGS = ['/SUBSYSTEM:WINDOWS', '/FORCE'])
 	conf.env.Append(LIBS=['SDLmain'])
 
-if not conf.CheckLibWithHeader('SDL', 'SDL.h', 'c++', "SDL_Init(0);", False):
+if not conf.CheckLibWithHeader('SDL', 'SDL.h"\nint main(int argc, char* argv[]) {/*', 'c++', "*/SDL_Init(0);", False):
 	Exit(1)
 	
 
@@ -140,10 +140,10 @@
 	smpeg_lib = 'smpeg_d'
 Export('smpeg_lib')
 
-if not conf.CheckLibWithHeader(smpeg_lib, 'smpeg/smpeg.h', 'c++', "SMPEG_new_data(malloc(42), 42, NULL, 0);", False):
+if not conf.CheckLibWithHeader(smpeg_lib, 'smpeg/smpeg.h"\nint main(int argc, char* argv[]) {/*', 'c++', "*/ SMPEG_new_data(malloc(42), 42, NULL, 0);", False):
 	Exit(1)
 
-if not conf.CheckLibWithHeader('SDL_image', 'SDL_image.h', 'c++', "IMG_Load(0);", False):
+if not conf.CheckLibWithHeader('SDL_image', 'SDL_image.h"\nint main(int argc, char* argv[]) {/*', 'c++', "*/IMG_Load(0);", False):
 	Exit(1)
 
 if not conf.CheckLibWithHeader('vorbisfile', 'vorbis/vorbisfile.h', 'c++', "ov_open(0, 0, 0, 0);", False):