zchunk: fix build on darwin

pkgs/development/libraries/zchunk/0001-meson-fix-argp-standalone.patch

···
+diff --git a/meson.build b/meson.build
+index 1c6b32d..aa7dd25 100644
+--- a/meson.build
++++ b/meson.build
+@@ -58,10 +58,10 @@ endif
+ 
+ # argp-standalone dependency (if required)
+ if build_machine.system() == 'windows' or build_machine.system() == 'darwin' or build_machine.system() == 'freebsd' or not cc.links('#include <argp.h>\nstatic error_t parse_opt (int key, char *arg, struct argp_state *state) { argp_usage(state); return 0; }; void main() {}')
+-    if fs.is_dir(join_paths([get_option('prefix'), 'include']))
+-        inc += include_directories(join_paths([get_option('prefix'), 'include']))
++    argplib = cc.find_library('argp', has_headers : ['argp.h'], required: false)
++    if not argplib.found()
++        argplib = dependency('argp-standalone')
+     endif
+-    argplib = cc.find_library('argp', dirs : join_paths([get_option('prefix'), 'lib']))
+ else
+     argplib = dependency('', required : false)
+ endif

pkgs/development/libraries/zchunk/default.nix

···
     hash = "sha256-7H1WF5VkpA65xCdEa0Sw4r4jj+kGhDVCMr5AeE+3Ii4=";
   };
 
+  # unbreak on darwin by finding argp-standalone, based on the patch from
+  # buildroot:
+  #    https://github.com/buildroot/buildroot/raw/master/package/zchunk/0001-meson-fix-argp-standalone-wrap-and-find_library.patch
+  patches = lib.optional stdenv.isDarwin ./0001-meson-fix-argp-standalone.patch;
+
   nativeBuildInputs = [
     meson
     ninja
···
     license = licenses.bsd2;
     maintainers = with maintainers; [ AndersonTorres ];
     platforms = platforms.unix;
-    broken = stdenv.isDarwin; # does not find argp-standalone
   };
 }