Get macos arm64 shadergen working

.gitignore

@@ -1,3 +1,6 @@
+# Mac.
+.DS_Store
+
 # Vim temporary files (apparently)
 *~
 # Visual studio stuff

unix_run_codegen.sh

@@ -0,0 +1,27 @@
+set -e
+
+if [ -d gen ]; then
+  echo "Codegen dir already exists"
+else
+    mkdir gen
+fi
+
+echo Shader Gen
+
+
+unameOut="$(uname -s)"
+# https://stackoverflow.com/questions/3466166/how-to-check-if-running-in-cygwin-mac-or-linux
+
+case "${unameOut}" in
+    Darwin*)   
+    if [[ $(uname -m) == 'arm64' ]]; then
+        SHADER_EXECUTABLE="thirdparty/sokol-shdc-mac-arm64"
+    else
+        echo "Haven't downloaded the x64 macos shader binary yet, sorry"
+    fi;;
+
+    Linux*)     echo "Linux not supported yet.";;
+    *)          echo "No idea what this machine is dude, sorry";;
+esac
+
+$SHADER_EXECUTABLE --input threedee.glsl --output gen/threedee.glsl.h --slang glsl300es:hlsl5:glsl330