AC_CHECK_HEADER() emits warnings when configuring for non-x86, because
the preprocessor check is OK but the compile check is not:
configure: WARNING: immintrin.h: present but cannot be compiled
configure: WARNING: immintrin.h: check for missing prerequisite headers?
configure: WARNING: immintrin.h: see the Autoconf documentation
configure: WARNING: immintrin.h: section "Present But Cannot Be Compiled"
configure: WARNING: immintrin.h: proceeding with the compiler's result
.. by adding DBUS_CFLAGS and IBUS_CFLAGS to CPPFLAGS:
configure: WARNING: dbus/dbus.h: accepted by the compiler, rejected by the preprocessor!
configure: WARNING: dbus/dbus.h: proceeding with the compiler's result
configure: WARNING: ibus-1.0/ibus.h: accepted by the compiler, rejected by the preprocessor!
configure: WARNING: ibus-1.0/ibus.h: proceeding with the compiler's result
Patch from Matt Whitlock:
There are actually two distinct classes of problems at play here.
On the one hand, libsdl2's configure.ac has some POSIX conformance
issues - namely, the use of 'echo -n' and the passage of arguments
containing embedded backslashes to 'echo', neither of which is
defined by POSIX. The attached patch takes care of these issues.
Cameron Cawley
stdlib: Added SDL_round, SDL_roundf, SDL_lround and SDL_lroundf
The default implementation is based on the one used in the Windows RT video driver.
Specifically this patch which does not invoke _AC_PATH_X_XMKMF and
_AC_PATH_X_DIRECT internal autoconf routines when cross-compiling:
http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=33c3a47c04ab70a4dd54963fe433a171bc03747f
Without this, CFLAGS would brokenly have system include paths like
-I/usr/include/X11 when cross-compiling e.g. for windows. (And it
also resulted in annoying imake crashes for my setup...)
Substring
I was trying the KMSDRM video backend with some very simple programs that were working ok on 2.0.12. The same code won?t work on the current dev branch and I get:
DEBUG: check_modesetting: probing ?/dev/dri/card0?
DEBUG: /dev/dri/card0 connector, encoder and CRTC counts are: 4 5 6
DEBUG: check_modesetting: probing ?/dev/dri/card0?
DEBUG: /dev/dri/card0 connector, encoder and CRTC counts are: 4 5 6
DEBUG: KMSDRM_VideoInit()
DEBUG: Opening device /dev/dri/card0
DEBUG: Opened DRM FD (3)
DEBUG: no atomic modesetting support.
DEBUG: Video subsystem has not been initialized
INFO: Using SDL video driver: (null)
DEBUG: Video subsystem has not been initialized
After carefully checking, the radeon driver doesn?t support atomic modesetting. That?s not the only problem : the same happens with the amdgpu driver if we disable Display Core (kernel parameter amdgpu.dc=0, which is required to get analogue outputs working).
This is a major regression in the KMSDRM driver.
Using atomic mode setting is great, but having no fallback to the "standard KMS" is bad.
configure output is practically unchanged. there are still lots of
AC_TRY_COMPILE/AC_TRY_LINK replacements needed to really eliminate
the warnings, but that's for another time.
