atomic fallback uses x86 assembler on non-x86 archs

[barracuda156]

Here is what happens when I build this with gcc-4.2 (an old compiler, but this code only asks for C99, so it is supported by implication) on a non-x86 platform:

mv -f .deps/tcpkali-tcpkali_expr.Tpo .deps/tcpkali-tcpkali_expr.Po
ccache /usr/bin/gcc-4.2 -DHAVE_CONFIG_H -I. -I..  -I../deps/libev -I../deps/libcows -I../deps/libstatsd/src -I../deps/HdrHistogram -I../deps/boyer-moore-horspool -I../deps/pcg-c-basic -isystem/opt/local/include/LegacySupport -I/opt/local/include -std=gnu99 -W -Wall -Wno-strict-aliasing -fno-strict-aliasing -pipe -Os -arch ppc -pthread -MT tcpkali-tcpkali.o -MD -MP -MF .deps/tcpkali-tcpkali.Tpo -c -o tcpkali-tcpkali.o `test -f 'tcpkali.c' || echo './'`tcpkali.c
mv -f .deps/tcpkali-tcpkali_expr_y.Tpo .deps/tcpkali-tcpkali_expr_y.Po
In file included from tcpkali_engine.h:33,
                 from tcpkali_statsd.h:34,
                 from tcpkali_statsd.c:33:
tcpkali_traffic_stats.h: In function ‘add_traffic_numbers_AtoN’:
tcpkali_traffic_stats.h:62: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:63: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:64: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:65: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:66: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:67: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
mv -f .deps/tcpkali-tcpkali_statsd.Tpo .deps/tcpkali-tcpkali_statsd.Po
mv -f .deps/tcpkali-tcpkali_expr_l.Tpo .deps/tcpkali-tcpkali_expr_l.Po
In file included from tcpkali_engine.h:33,
                 from tcpkali.h:31,
                 from tcpkali_engine.c:56:
tcpkali_traffic_stats.h: In function ‘add_traffic_numbers_AtoN’:
tcpkali_traffic_stats.h:62: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:63: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:64: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:65: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:66: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:67: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
{standard input}:1182:Invalid mnemonic 'lock'
{standard input}:1185:Invalid mnemonic 'lock'
{standard input}:1188:Invalid mnemonic 'lock'
{standard input}:1192:Invalid mnemonic 'lock'
{standard input}:1196:Invalid mnemonic 'lock'
{standard input}:1200:Invalid mnemonic 'lock'
{standard input}:1311:Invalid mnemonic 'lock'
{standard input}:1391:Invalid mnemonic 'lock'
{standard input}:1394:Invalid mnemonic 'lock'
{standard input}:1397:Invalid mnemonic 'lock'
{standard input}:3824:Invalid mnemonic 'lock'
{standard input}:3828:Invalid mnemonic 'lock'
{standard input}:5526:Invalid mnemonic 'lock'
{standard input}:5948:Invalid mnemonic 'lock'
{standard input}:6011:Invalid mnemonic 'lock'
{standard input}:6053:Invalid mnemonic 'lock'
{standard input}:6186:Invalid mnemonic 'lock'
{standard input}:6190:Invalid mnemonic 'lock'
{standard input}:6298:Invalid mnemonic 'lock'
{standard input}:6380:Invalid mnemonic 'lock'
{standard input}:6407:Invalid mnemonic 'lock'
{standard input}:6421:Invalid mnemonic 'lock'
make[2]: *** [tcpkali-tcpkali_engine.o] Error 1
make[2]: *** Waiting for unfinished jobs....
In file included from tcpkali_engine.h:33,
                 from tcpkali_run.h:33,
                 from tcpkali_run.c:36:
tcpkali_traffic_stats.h: In function ‘add_traffic_numbers_AtoN’:
tcpkali_traffic_stats.h:62: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:63: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:64: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:65: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:66: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:67: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
mv -f .deps/tcpkali-tcpkali_run.Tpo .deps/tcpkali-tcpkali_run.Po
In file included from tcpkali_engine.h:33,
                 from tcpkali.h:31,
                 from tcpkali.c:49:
tcpkali_traffic_stats.h: In function ‘add_traffic_numbers_AtoN’:
tcpkali_traffic_stats.h:62: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:63: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:64: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:65: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:66: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
tcpkali_traffic_stats.h:67: warning: passing argument 1 of ‘atomic_wide_get’ discards qualifiers from pointer target type
mv -f .deps/tcpkali-tcpkali.Tpo .deps/tcpkali-tcpkali.Po
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_net_tcpkali/tcpkali/work/tcpkali-1.1.1/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_net_tcpkali/tcpkali/work/tcpkali-1.1.1'
make: *** [all] Error 2

This is because src/tcpkali_atomic.h uses x86 assembler unconditionally in its fallback implementation. This is obviously wrong: if there is no possibility or motivation to have a cross-platform implementation, at least it should fail with a meaningful error message, and preferably already at configure stage.