Update to Fedora 39, update all toolchains

- Base image: Fedora 39
- SCons: 4.5.2
- Linux: GCC 10.2.0 built against glibc 2.19, binutils 2.35.1
- Windows: MinGW 11.0.0, GCC 13.2.1, binutils 2.40
- Web: Emscripten 3.1.39
- Android: Android NDK 23.2.8568313, build-tools 33.0.2, platform android-33, CMake 3.22.1, JDK 17
  CMake 3.22.1, JDK 17
- macOS: Xcode 15.0 with Apple Clang (LLVM 16.0.0), MacOSX SDK 14.0
- iOS: Xcode 15.0 with Apple Clang (LLVM 16.0.0), iPhoneOS SDK 17.0

Switches macOS/iOS builds to use Apple Clang, to maximize compatibility with
upstream Xcode.

Also add gettext which is needed by Godot build scripts to compile PO files
to MO.

Dockerfile.base

@@ -1,4 +1,4 @@
-FROM fedora:36
+FROM fedora:39
 
 WORKDIR /root
 
@@ -6,8 +6,8 @@ ENV DOTNET_NOLOGO=1
 ENV DOTNET_CLI_TELEMETRY_OPTOUT=1
 
 RUN dnf -y install --setopt=install_weak_deps=False \
-      bash bzip2 curl file findutils git make nano patch pkgconfig python3-pip unzip which xz \
+      bash bzip2 curl file findutils gettext git make nano patch pkgconfig python3-pip unzip which xz \
       dotnet-sdk-6.0 && \
-    pip install scons==4.4.0
+    pip install scons==4.5.2
 
 CMD /bin/bash