bootstrap: use better defaults for Haiku

These values are patched into that file by Haiku since 2.8.1.
Haiku no longer defines __BEOS__
check for Haiku only with __HAIKU__
FindLua51: do not try to link libm on BeOS

This includes Haiku, which currently is treated as BeOS. The ComplexOneConfig
test already knew about this.
FindGLUT: BeOS does not have libXi and libXmu
FindOpenGL: add Haiku paths

Also check the HP-UX specific paths only when on HP-UX.
Allow target_link_libraries with IMPORTED targets.

This makes it possible to use:

 target_link_libraries(foo LINK_INTERFACE_LIBRARIES bar)

where foo is an IMPORTED target. Other tll() signatures are not
allowed.
Add the -Wundef flag when compiling CMake.
Keep track of properties used to determine linker libraries.

Those properties can't later be implicitly defined by the interface
of those link libraries.
Add API to calculate link-interface-dependent bool properties or error.

This new method checks that the property FOO on a target is consistent
with the INTERFACE_FOO properties of its dependees. If they are not the
consistent, an error is reported. 'Consistent' means that iff the
property is set, it must have the same boolean value as all other
related properties.
KWIML: Teach ABI about 'long long' on older GNU

Old GNU compilers do not define __SIZEOF_LONG_LONG__ or
__LONG_LONG_MAX__ but do provide a 64-bit 'long long' type.

Suggested-by: Rolf Eike Beer <eike@sf-mail.de>
Merge branch 'upstream-kwiml' into update-KWIML
CMake Nightly Date Stamp
FindQt4: Add INTERFACE includes and defines to Qt4 targets
Add the target_include_directories command.

This is a convenience API to populate the corresponding properties.
Add the target_compile_definitions command.

This is a convenience API to populate the corresponding properties.
Process the INTERFACE_PIC property from linked dependencies

This allows a dependee to inform a target that it should have its
POSITION_INDEPENDENT_CODE property set to ON, or OFF. The value of
the POSITION_INDEPENDENT_CODE property, if set, must be consistent
with any INTERFACE_POSITION_INDEPENDENT_CODE properties on dependees.

Add a test covering the consistency checks on platforms where they run.
Merge topic 'update-KWIML'

32fb667 Merge branch 'upstream-kwiml' into update-KWIML
9fdfe07 KWIML: Teach ABI about 'long long' on older GNU
Merge topic 'Haiku'

0380f36 FindOpenGL: add Haiku paths
8e9630c FindGLUT: BeOS does not have libXi and libXmu
50bfedf FindLua51: do not try to link libm on BeOS
3d2e6a0 check for Haiku only with __HAIKU__
7a1b961 Haiku no longer defines __BEOS__
ed96d9a bootstrap: use better defaults for Haiku
Merge topic 'tll-IMPORTED-targets'

9cfe4f1 Allow target_link_libraries with IMPORTED targets.