The following steps will install the latest compiler from source
Download gcc 6.3.0 from https://gcc.gnu.org/mirrors.html I used the Japanese mirror as this is the closest location to me http://ftp.tsukuba.wide.ad.jp/software/gcc/releases/gcc-6.3.0/gcc-6.3.0.tar.gz
If the above make command fails please use "make clean pristine" and then remove and remake the build directory. This will clean up and prepare the environment for another attempt. A common reason for failure on virtual machines is lack of RAM (if you don't have enough RAM you may get an error like this "recipe for target 's-attrtab' failed"). Otherwise, if all goes well in about 30 to 60 minutes the compiler will be ready and we will move on to the next steps.
Build configurations for Visual Studio, GNU Make, Ninja, and Xcode can be created using [cmake](https://cmake.org/) v3.2+. A full list of cmake generators can be found [here](https://cmake.org/cmake/help/v3.0/manual/cmake-generators.7.html). A basic build would look like (starting in the root xlnt directory):
```bash
mkdir build
cd build
cmake ..
make -j8
```
The resulting shared (e.g. libxlnt.dylib) library would be found in the build/lib directory. Other cmake configuration options for xlnt can be found using "cmake -LH". These options include building a static library instead of shared and whether to build sample executables or not. An example of building a static library with an Xcode project:
```bash
mkdir build
cd build
cmake -D STATIC=ON -G Xcode ..
cmake --build .
cd bin && ./xlnt.test
```
*Note for Windows: cmake defaults to building a 32-bit library project. To build a 64-bit library, use the Win64 generator*