TODO

 o Add new target which reports on build space used per component
 o If debugging enabled, component.makefile should warn on undefined
   variables.
 o Add lmsbw_ prefix to functions
 o Error messages should print component names for disambiguation.
 o Figure out why generate-rules.mk causes errors when put in
   lmsbw-system.mk.
 o Figure out why error occurs if assignment to __dsm in declare_source_component() is removed.
 o Support LDFLAGS wrapping per-component.
 o One could imagine an extension to the component system.  A plugin
   for subdirectory makefiles which would has CFLAGS, the relative
   pathname and the contents of the source file.  The hash would be
   sent to an official build server asking if an object file for that
   configuration exists on the build server.  If it does, the object
   file is returned.  If it does not exist, then it should be built
   locally.
 o Applying patches should be part of lmsbw
 o Add facility to trace rule execution using $@, $^, etc.
 o Remove 'hypothetical' footnote in documentation when a pure
   download component is created.
 o remove all reference to lmsbw_c_cflags and 'cflags'.
 o Add -MMD to default cflags?
 o Rename '__gcv' to '__lmsbw_gcv'
 o Add & document 'poc' field.  It's a point of contact.  Add to report.
 o Should the 'global-settings' have 'image' and 'build' versions?
 o doc/reference 'make clean' leaves lof and idx files
 o What would it mean for a component to have more than one source directory?
 o Document lmsbw-graph script.
 o Copying the destdir to install directory using the
   LMSBW_INSTALL_DESTDIR script does not handle multiple API
   directories.
 o Add declared 'adapter' to report
 o Generate the adapter rules

 o Should all LMSBW-specific variables be put into an associative array?

 o document 'exports-api' component field

 o source-api sample does not work because of lmsbw-install-destdir.
   It's only linking the declared API directory, not the entire
   destdire directory.

o When the build fails, the component that failed is not always displayed.   

o When deleting the DESTDIR, files present should be removed from the
  global install directory.

o component 'clean' verb should delete all installed files?  

o guarantee that custom toolchain script declarations reference an
  existing file.  Produce an error if not.

o Need a declare function for custom toolchains.

o Need an error for missing custom toolchains

o Duplicate use of E1025