Derive operator!= from operator== (#1660)

Author: Rangi42

.github/workflows/create-release-artifacts.yml

@@ -100,7 +100,7 @@ jobs:
           path: rgbds-${{ env.version }}-macos.zip
 
   linux:
-    runs-on: ubuntu-20.04 # Oldest supported, for best glibc compatibility.
+    runs-on: ubuntu-22.04 # Oldest supported, for best glibc compatibility.
     steps:
       - name: Get version from tag
         shell: bash
@@ -112,7 +112,7 @@ jobs:
       - name: Install deps
         shell: bash
         run: |
-          ./.github/scripts/install_deps.sh ubuntu-20.04
+          ./.github/scripts/install_deps.sh ubuntu-22.04
       - name: Build binaries
         run: |
           make -kj WARNFLAGS="-Wall -Wextra -pedantic -static" PKG_CONFIG="pkg-config --static" Q=

.github/workflows/testing.yml

@@ -7,7 +7,7 @@ jobs:
   unix:
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-14]
+        os: [ubuntu-22.04, macos-14]
         cxx: [g++, clang++]
         buildsys: [make, cmake]
         exclude:

include/gfx/rgba.hpp

@@ -38,7 +38,6 @@ struct Rgba {
 	}
 
 	bool operator==(Rgba const &rhs) const { return toCSS() == rhs.toCSS(); }
-	bool operator!=(Rgba const &rhs) const { return !operator==(rhs); }
 
 	// CGB colors are RGB555, so we use bit 15 to signify that the color is transparent instead
 	// Since the rest of the bits don't matter then, we return 0x8000 exactly.

include/itertools.hpp

@@ -25,7 +25,6 @@ class EnumSeq {
 		auto operator*() const { return _value; }
 
 		bool operator==(Iterator const &rhs) const { return _value == rhs._value; }
-		bool operator!=(Iterator const &rhs) const { return !operator==(rhs); }
 	};
 
 public:
@@ -59,7 +58,6 @@ class ZipIterator {
 	bool operator==(ZipIterator const &rhs) const {
 		return std::get<0>(_iters) == std::get<0>(rhs._iters);
 	}
-	bool operator!=(ZipIterator const &rhs) const { return !operator==(rhs); }
 };
 
 template<typename... Ts>

src/gfx/pal_packing.cpp

@@ -87,7 +87,6 @@ class AssignedProtos {
 		Iter() = default;
 
 		bool operator==(Iter const &rhs) const { return _iter == rhs._iter; }
-		bool operator!=(Iter const &rhs) const { return !operator==(rhs); }
 
 		Iter &operator++() {
 			++_iter;

src/gfx/process.cpp

@@ -466,7 +466,6 @@ class Png {
 			}
 
 			bool operator==(Iterator const &rhs) const { return coords() == rhs.coords(); }
-			bool operator!=(Iterator const &rhs) const { return !operator==(rhs); }
 		};
 
 	public: