Per issue from MattWatt, gcc for Raspberry Pi warns about alignment
issues.
Per issue from kreator, clang warns about alignment issues on OS X.
However, it does not warn on x86_64-pc-linux-gnu.
GCC only warns when compiling for a target architecture that requires
alignment, so it does not warn for i686-pc-linux-gnu or
x86_64-pc-linux-gnu.
Using this warning would be nice, but since it only triggers on
architectures not maintained by active developers, it causes more
trouble than it may solve.
Alignment sensitive users will have to get by with software fixups until
an active developer begins targeting alignment sensitive hardware.
Reported-by: MattWatt <https://github.com/dxx-rebirth/dxx-rebirth/issues/119>
Reported-by: kreatordxx <https://github.com/dxx-rebirth/dxx-rebirth/issues/120>
Some builds of SDL lack joystick support. Rebirth requires joystick
support in SDL, even if the user never connects a joystick. Add a call
to SDL_NumJoysticks during the SDL test so that systems without SDL
joystick support fail the "usable library SDL" test.
Test check_compiler_template_parentheses_warning probes for a bug in
gcc-4.6. Upstream fixed the bug in gcc-4.7. Using gcc-4.6 is no longer
supported, so remove the test for the bug.
clang does not support -flto=N syntax for parallel LTO.
Remove -fno-fat-lto-objects too. clang does not understand it;
gcc 4.9 and later default to non-fat LTO.
Fixes: 1037a92d60 ("Allow parallel lto")
Previously, SConstruct tested whether static_assert worked with trivial
constant expressions. Extend the test to more complicated expressions
like the ones used in the program.
Replace the typedef based approach with an inline enum to avoid warnings
about unused local typedefs.
Allow use with compilers that lack working static_assert or that cannot
accept complicated expressions. Add a non-checking definition that uses
the input parameter. This prevents warnings when types or constants are
used only for the static_assert.