doc: remove Clang 3.8 references, advertise Clang 6+ as supported.

Hey, do you also remember the times where people were excited to upgrade
from Clang 3.6 to 3.7, GCC 4.7 to 4.8 or Firefox 1.1 to Firefox 1.5? Not
Clang 12 to 14, GCC 10 to 13 or Chrome 102 to 126.

doc/building.dox

@@ -38,8 +38,9 @@ namespace Magnum {
 Minimal set of tools and libraries required for building is:
 
 -   C++ compiler with good C++11 support. Compilers which are tested to have
-    everything needed are **GCC** >= 4.8.1, **Clang** >= 3.3 and **MSVC**
-    >= 2015. On Windows you can also use **Clang-CL** or **MinGW-w64**.
+    everything needed are **GCC** >= 4.8.1, **Clang** >= 6 (or equivalently
+    **Apple Clang** >= 10) and **MSVC** >= 2015. On Windows you can also use
+    **Clang-CL** or **MinGW-w64**.
 -   **CMake** >= 3.4
 -   **Corrade** --- Plugin management and utility library. See
     @ref building-corrade "Corrade download and installation guide" for more

doc/changelog.dox

@@ -569,6 +569,9 @@ See also:
 
 @subsection changelog-latest-buildsystem Build system
 
+-   The oldest supported Clang version is now 6.0 (available on Ubuntu 18.04),
+    or equivalently Apple Clang 10.0 (Xcode 10). Oldest supported GCC version
+    is still 4.8.
 -   Fixed compilation of the @ref GL library on macOS with ANGLE --- new code
     assumed macOS is always desktop GL (see [mosra/magnum#452](https://github.com/mosra/magnum/issues/452))
 -   Avoiding conflicts of Magnum's own GL headers with `GLES3/gl32.h` (see

src/Magnum/ShaderTools/AbstractConverter.cpp

@@ -287,7 +287,7 @@ AbstractConverter::convertDataToData(const Stage stage, const Containers::ArrayV
     CORRADE_ASSERT(!out || !out->deleter(),
         "ShaderTools::AbstractConverter::convertDataToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::OptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -435,7 +435,7 @@ AbstractConverter::convertFileToData(const Stage stage, const Containers::String
     CORRADE_ASSERT(!out || !out->deleter(),
         "ShaderTools::AbstractConverter::convertFileToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::OptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -479,7 +479,7 @@ AbstractConverter::linkDataToData(const Containers::ArrayView<const Containers::
     CORRADE_ASSERT(!out || !out->deleter(),
         "ShaderTools::AbstractConverter::linkDataToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::OptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -693,7 +693,7 @@ AbstractConverter::linkFilesToData(const Containers::ArrayView<const Containers:
     CORRADE_ASSERT(!out || !out->deleter(),
         "ShaderTools::AbstractConverter::linkFilesToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::OptionalButAlsoArray<char>{std::move(out)};
     #else

src/Magnum/Trade/AbstractImageConverter.cpp

@@ -308,7 +308,7 @@ AbstractImageConverter::convertToData(const ImageView1D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -341,7 +341,7 @@ AbstractImageConverter::convertToData(const ImageView2D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -381,7 +381,7 @@ AbstractImageConverter::convertToData(const ImageView3D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -414,7 +414,7 @@ AbstractImageConverter::convertToData(const CompressedImageView1D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -447,7 +447,7 @@ AbstractImageConverter::convertToData(const CompressedImageView2D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -487,7 +487,7 @@ AbstractImageConverter::convertToData(const CompressedImageView3D& image) {
     Containers::Optional<Containers::Array<char>> out = doConvertToData(image);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -603,7 +603,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const ImageVie
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -642,7 +642,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const ImageVie
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -681,7 +681,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const ImageVie
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -720,7 +720,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const Compress
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -759,7 +759,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const Compress
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else
@@ -798,7 +798,7 @@ AbstractImageConverter::convertToData(const Containers::ArrayView<const Compress
     Containers::Optional<Containers::Array<char>> out = doConvertToData(imageLevels);
     CORRADE_ASSERT(!out || !out->deleter(), "Trade::AbstractImageConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::ImageConverterOptionalButAlsoArray<char>{std::move(out)};
     #else

src/Magnum/Trade/AbstractSceneConverter.cpp

@@ -163,7 +163,7 @@ AbstractSceneConverter::convertToData(const MeshData& mesh) {
     CORRADE_ASSERT(!out || !out->deleter() || out->deleter() == static_cast<void(*)(char*, std::size_t)>(Implementation::nonOwnedArrayDeleter) || out->deleter() == ArrayAllocator<char>::deleter,
         "Trade::AbstractSceneConverter::convertToData(): implementation is not allowed to use a custom Array deleter", {});
 
-    /* GCC 4.8 and Clang 3.8 need an explicit conversion here */
+    /* GCC 4.8 needs an explicit conversion here */
     #ifdef MAGNUM_BUILD_DEPRECATED
     return Implementation::SceneConverterOptionalButAlsoArray<char>{std::move(out)};
     #else

src/Magnum/Trade/Test/AbstractSceneConverterTest.cpp

@@ -516,7 +516,7 @@ void AbstractSceneConverterTest::convertMeshToDataGrowableDeleter() {
             Containers::Array<char> out;
             Containers::arrayAppend<ArrayAllocator>(out, {'h', 'e', 'l', 'l', 'o'});
 
-            /* GCC 4.8 and Clang 3.8 need extra help here */
+            /* GCC 4.8 needs extra help here */
             return Containers::optional(std::move(out));
         }
     } converter;

src/MagnumPlugins/TgaImageConverter/TgaImageConverter.cpp

@@ -86,7 +86,7 @@ Containers::Optional<Containers::Array<char>> TgaImageConverter::doConvertToData
             pixel = Math::gather<'b', 'g', 'r', 'a'>(pixel);
     }
 
-    /* GCC 4.8 and Clang 3.8 need extra help here */
+    /* GCC 4.8 needs extra help here */
     return Containers::optional(std::move(data));
 }