build: fix MinGW build failures and update documentation

This includes updating the ANGLE dependency to the latest commit in our
fork which fixes a build issue with GCC.

Additionally, a minor change to the build configuration was needed for
building under 64-bit MinGW, which doesn't support `--large-address-aware`.

With those in place, the documentation for building under MinGW is updated
with working instructions and a recommendation to use MSYS2 for easier
installation of the required tools.

Author: iscgar

CMakeLists.txt

@@ -104,10 +104,12 @@ endif()
 if(MINGW)
     set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -static-libgcc")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -static-libgcc -static-libstdc++")
-    # Link 32 bit SolveSpace with --large-address-aware which allows it to access
-    # up to 3GB on a properly configured 32 bit Windows and up to 4GB on 64 bit.
-    # See https://msdn.microsoft.com/en-us/library/aa366778
-    set(CMAKE_EXE_LINKER_FLAGS "-Wl,--large-address-aware")
+    if(CMAKE_SIZEOF_VOID_P EQUAL 4)
+        # Link 32 bit SolveSpace with --large-address-aware which allows it to access
+        # up to 3GB on a properly configured 32 bit Windows and up to 4GB on 64 bit.
+        # See https://msdn.microsoft.com/en-us/library/aa366778
+        set(CMAKE_EXE_LINKER_FLAGS "-Wl,--large-address-aware")
+    endif()
 endif()
 
 # Ensure that all platforms use 64-bit IEEE floating point operations for consistency;

README.md

@@ -307,19 +307,34 @@ nmake
 It is also possible to build SolveSpace using [MinGW][mingw], though
 Space Navigator support will be disabled.
 
-First, ensure that git and gcc are in your `$PATH`. Then, run the following
-in bash:
+The easiest way to build using MinGW is with [MSYS2][msys2]. If you're not using MSYS2, skip
+the installation instructions and ensure that git, cmake, ninja, and gcc are in your `$PATH`.
+
+With MSYS2, you can build either a 32-bit binary or a 64-bit one, depending on the compiler
+used. The following instructions assume you're running the commands inside an `MSYS2 MINGW64`
+terminal window and building a 64-bit version. If you want to build a 32-bit version, you'll
+need to run the commands in an `MSYS2 MINGW32` terminal window and replace `x86_64`
+with `i686` in the installation commands.
+
+First, install Git, GCC, CMake, and Ninja:
+
+```sh
+pacman -Sy mingw-w64-x86_64-git mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake mingw-w64-x86_64-ninja
+```
+
+Then, run the following in bash:
 
 ```sh
 mkdir build
 cd build
-cmake .. -DCMAKE_BUILD_TYPE=Release
-make
+cmake .. -DCMAKE_BUILD_TYPE=Release -GNinja
+ninja
 ```
 
 [gitwin]: https://git-scm.com/download/win
-[cmakewin]: http://www.cmake.org/download/#latest
+[cmakewin]: https://www.cmake.org/download/#latest
 [mingw]: http://www.mingw.org/
+[msys2]: https://www.msys2.org/
 
 ## Contributing