ci: Test GCC 12 on Linux (#82)

Signed-off-by: Julien Jerphanion <git@jjerphan.xyz>

.github/workflows/linux.yml

@@ -22,6 +22,7 @@ jobs:
  # - {compiler: clang, version: '16', config-flags: '-DCMAKE_CXX_FLAGS=-stdlib=libc++', stdlib: 'libc++-17' }
  - {compiler: clang, version: '17', config-flags: '', stdlib: 'libstdc++-13' }
  # - {compiler: clang, version: '17', config-flags: '-DCMAKE_CXX_FLAGS=-stdlib=libc++', stdlib: 'libc++-17' }
+ - {compiler: gcc, version: '12', config-flags: '' }
  - {compiler: gcc, version: '13', config-flags: '' }
 
  config:

include/sparrow/iterator.hpp

@@ -121,7 +121,8 @@ namespace sparrow
  it.advance(n);
  }
 
-#if _WIN32 // Workaround for access issue with msvc, when friend is involved
+// On MSVC and GCC < 13, those methods need to be public to be accessible by friend functions.
+#if _WIN32 || __GNUC__ < 13
 
  public:
 
@@ -143,11 +144,14 @@ namespace sparrow
  {
  return lhs.less_than(rhs);
  }
-#if _WIN32 // Workaround for access issue with msvc, when friend is involved
+
+// On MSVC and GCC < 13, those methods need to be public to be accessible by friend functions.
+#if _WIN32 || __GNUC__ < 13
 
  private:
 
 #endif
+
  template <class Derived, class E, class T, class R, class D>
  friend class iterator_root_base;