These are the base libraries for the GNU Modula-2 compiler. These modules originally came from the M2F compiler and have been cleaned up and extended. They provide a basic interface to the underlying operating system via libc. They also include a number of libraries to allow access to compiler built-ins. Perhaps the largest difference to PIM and ISO libraries is the DynamicString module which declares the type String. The heavy use of this opaque data type results in a number of equivalent modules that can either handle ARRAY OF CHAR or String.
These modules have been extensively tested and are used throughout building the GNU Modula-2 compiler.