This subdirectory contains infrastructure which is not put into

installed libraries, but may be linked into programs (installed or

not) and tests.

# Error-checking wrappers

These wrappers test for error return codes an terminate the process on

error.  They are declared in these header files:

* support.h

* xsignal.h

* xthread.h

In general, new wrappers should be added to support.h if possible.

However, support.h must remain fully compatible with C90 and therefore

cannot include headers which use identifers not reserved in C90.  If

the wrappers need additional types, additional headers such as

signal.h need to be introduced.

# Test framework

The test framework provides a main program for tests, including a

timeout for hanging tests.  See README-testing.c for a minimal

example, and test-driver.c for details how to use it.  The following

header files provide related declarations:

* check.h

* temp_file.h

* test-driver.h