rsb: Move "Why Build from Source?" to own chapter

rsb/index.rst

@@ -28,6 +28,7 @@ RTEMS Source Builder (|version|).
     :numbered:
 
     source-builder
+    why-build-from-source.rst
     building-tools-and-rtems.rst
     project-sets
     cross-canadian-cross

rsb/source-builder.rst

@@ -77,62 +77,6 @@ configuration can read the remaining sections.
    If you think you have found a problem please see :ref:`Bugs, Crashes, and
    Build Failures`.
 
-Why Build from Source?
-----------------------
-
-The RTEMS Source Builder is not a replacement for the binary install systems
-you have with commercial operating systems or open source operating system
-distributions. Those products and distributions are critically important and
-are the base that allows the RSB to work. The RTEMS Source Builder sits
-somewhere between you manually entering the commands to build a tool set and a
-tool such as ``yum`` or ``apt-get`` to install binary packages made
-specifically for your host operating system. Building manually or installing a
-binary package from a remote repository are valid and real alternatives. The
-RSB provides the specific service of repeatably being able to build tool sets
-from source code. The process leaves you with the source code used to build
-the tools and the ability to rebuilt it.
-
-If you are developing a system or product that has a long shelf life or is used
-in a critical piece of infrastructure that has a long life cycle being able to
-build from source is important. It insulates the project from the fast ever
-changing world of the host development machines. If your tool set is binary and
-you have lost the ability to build it you have lost a degree of control and
-flexibility open source gives you. Fast moving host environments are
-fantastic. We have powerful multi-core computers with huge amounts of memory
-and state of the art operating systems to run on them however the product or
-project you are part of may need to be maintained well past the life time of
-these host. Being able to build from source an important and critical part of
-this process because you can move to a newer host and create an equivalent tool
-set.
-
-Building from source provides you with control over the configuration of the
-package you are building. If all or the most important dependent parts are
-built from source you limit the exposure to host variations. For example the
-GNU C compiler (gcc) currently uses a number of 3rd party libraries internally
-(gmp, mpfr, etc). If your validated compiler generating code for your target
-processor is dynamically linked against the host's version of these libraries
-any change in the host's configuration may effect you. The changes the host's
-package management system makes may be perfectly reasonable in relation to the
-distribution being managed however this may not extend to you and your
-tools. Building your tools from source and controlling the specific version of
-these dependent parts means you are not exposing yourself to unexpected and
-often difficult to resolve problems. On the other side you need to make sure
-your tools build and work with newer versions of the host operating
-system. Given the stability of standards based libraries like ``libc`` and ever
-improving support for standard header file locations this task is becoming
-easier.
-
-The RTEMS Source Builder is designed to be audited and incorporated into a
-project's verification and validation process. If your project is developing
-critical applications that needs to be traced from source to executable code in
-the target, you need to also consider the tools and how to track them.
-
-If your IT department maintains all your computers and you do not have suitable
-rights to install binary packages, building from source lets you create your
-own tool set that you install under your home directory. Avoiding installing
-any extra packages as a super user is always helpful in maintaining a secure
-computing environment.
-
 Controlling the Tools Build
 ---------------------------
 

rsb/why-build-from-source.rst

@@ -0,0 +1,59 @@
+.. SPDX-License-Identifier: CC-BY-SA-4.0
+
+.. Copyright (C) 2012, 2016 Chris Johns <chrisj@rtems.org>
+
+Why Build from Source?
+======================
+
+The RTEMS Source Builder is not a replacement for the binary install systems
+you have with commercial operating systems or open source operating system
+distributions. Those products and distributions are critically important and
+are the base that allows the RSB to work. The RTEMS Source Builder sits
+somewhere between you manually entering the commands to build a tool set and a
+tool such as ``yum`` or ``apt-get`` to install binary packages made
+specifically for your host operating system. Building manually or installing a
+binary package from a remote repository are valid and real alternatives. The
+RSB provides the specific service of repeatably being able to build tool sets
+from source code. The process leaves you with the source code used to build
+the tools and the ability to rebuilt it.
+
+If you are developing a system or product that has a long shelf life or is used
+in a critical piece of infrastructure that has a long life cycle being able to
+build from source is important. It insulates the project from the fast ever
+changing world of the host development machines. If your tool set is binary and
+you have lost the ability to build it you have lost a degree of control and
+flexibility open source gives you. Fast moving host environments are
+fantastic. We have powerful multi-core computers with huge amounts of memory
+and state of the art operating systems to run on them however the product or
+project you are part of may need to be maintained well past the life time of
+these host. Being able to build from source an important and critical part of
+this process because you can move to a newer host and create an equivalent tool
+set.
+
+Building from source provides you with control over the configuration of the
+package you are building. If all or the most important dependent parts are
+built from source you limit the exposure to host variations. For example the
+GNU C compiler (gcc) currently uses a number of 3rd party libraries internally
+(gmp, mpfr, etc). If your validated compiler generating code for your target
+processor is dynamically linked against the host's version of these libraries
+any change in the host's configuration may effect you. The changes the host's
+package management system makes may be perfectly reasonable in relation to the
+distribution being managed however this may not extend to you and your
+tools. Building your tools from source and controlling the specific version of
+these dependent parts means you are not exposing yourself to unexpected and
+often difficult to resolve problems. On the other side you need to make sure
+your tools build and work with newer versions of the host operating
+system. Given the stability of standards based libraries like ``libc`` and ever
+improving support for standard header file locations this task is becoming
+easier.
+
+The RTEMS Source Builder is designed to be audited and incorporated into a
+project's verification and validation process. If your project is developing
+critical applications that needs to be traced from source to executable code in
+the target, you need to also consider the tools and how to track them.
+
+If your IT department maintains all your computers and you do not have suitable
+rights to install binary packages, building from source lets you create your
+own tool set that you install under your home directory. Avoiding installing
+any extra packages as a super user is always helpful in maintaining a secure
+computing environment.