Clang is smart enough to recognize that "*(int*)0=0" invokes undefined
behavior, warns, and produces an "undefined instruction". The message
in commit "Avoid Clang optimizer bug in testProcess-[45]" (2010-07-02)
is incorrect; this is not a Clang bug. It really is undefined
behavior. Use "*(int*)1=0" to produce a crash instead.
Clang's optimizer, as of clang version 2.8 (trunk 107463), produces the
undefined instruction 'ud2' for the code "*(int*)0=0" on OS X x86_64.
It causes our crash tests to fail because the child process exits with
an invalid instruction instead of a segmentation fault. Work around the
bug by using "*(int*)1=0" in this case.
Add option KWSYS_TEST_BOGUS_FAILURES that can be set by a containing
project or in the CMake cache to list tests known to fail consistently
on a buggy system.
Since commit "Provide unix-sytle command line parsing" (2009-07-13) the
reference to KWSYS_C_HAS_PTRDIFF_T in System.c has been meaningless
because the macro was never passed to the compiler!
The DynamicLoader::LibPrefix and DynamicLoader::LibExtension methods
previously hard-coded the module name components for each platform. Set
them from the CMAKE_SHARED_MODULE_PREFIX and CMAKE_SHARED_MODULE_SUFFIX
CMake variables instead. This ensures consistency in a program that
uses these methods to construct the file names for its own modules.
The CopyFileIfDifferent, CopyFileAlways, CopyAFile and CopyADirectory
methods should always copy permissions. The special cases in which a
caller would pass copyPermissions=false should be handled at the call
site. The parameter needlessly complicates the interface and semantics
of these methods.
