Merge installer folder with internal

Internal/unix_gcc_build.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+for gcc_version in "$@"
+do
+    image_name=mostlyportable-gcc-image
+    container_name=mostlyportable-gcc
+
+    docker build -t ${image_name} --build-arg GCC_VERSION=${gcc_version} . || exit
+    docker container rm ${container_name} > /dev/null 2>&1
+    docker create --name ${container_name} ${image_name} || exit
+
+    mkdir --parent build || exit
+    docker cp ${container_name}:/usr/local/docker/mostlyportable-gcc/mostly-built/gcc-mostlyportable-${gcc_version} . || exit
+
+    docker container rm ${container_name} || exit
+done
+
+if [[ $EUID == 0 ]]; then
+    chown --recursive ${USER} gcc-mostlyportable-*
+fi