different value for same entry in config.log of 2.19.4 and 2.19.5

[Tiger Big <glib mailist gmail com>]

I'm compiling glib on solaris10(x86)

for glib version =< 2.19.4, always success; but for version > =2.19.5, always fail, the output is like following:

/bin/bash ../libtool --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I. -I..  -I..  -DG_LOG_DOMAIN=\"GLib\" -DG_ENABLE_DEBUG -DG_DISABLE_DEPRECATED -DGLIB_COMPILATION -DPCRE_STATIC -DG_DISABLE_SINGLE_INCLUDES -D_REENTRANT -D_PTHREADS  -g -O2 -Wall -MT gatomic.lo -MD -MP -MF .deps/gatomic.Tpo -c -o gatomic.lo gatomic.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -I.. -DG_LOG_DOMAIN=\"GLib\" -DG_ENABLE_DEBUG -DG_DISABLE_DEPRECATED -DGLIB_COMPILATION -DPCRE_STATIC -DG_DISABLE_SINGLE_INCLUDES -D_REENTRANT -D_PTHREADS -g -O2 -Wall -MT gatomic.lo -MD -MP -MF .deps/gatomic.Tpo -c gatomic.c  -fPIC -DPIC -o .libs/gatomic.o
/var/tmp//ccdMPXmo.s: Assembler messages:
/var/tmp//ccdMPXmo.s:79: Error: Incorrect register `%ecx' used with `q' suffix
gmake[4]: *** [gatomic.lo] Error 1
gmake[4]: Leaving directory `/usr/local/glib-2.19.5/glib'
gmake[3]: *** [all-recursive] Error 1
gmake[3]: Leaving directory `/usr/local/glib-2.19.5/glib'
gmake[2]: *** [all] Error 2
gmake[2]: Leaving directory `/usr/local/glib-2.19.5/glib'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory `/usr/local/glib-2.19.5'
gmake: *** [all] Error 2

I've checked config.log of 2.19.4 and 2.19.5, and found the following difference:

"Checking build system type"
2.19.4 i386-pc-solaris2.10
2.19.5 x86_64-pc-solaris2.10

"Checking host system type" has the same result as above

"checking whether to use assembler code for atomic operations"
2.19.4 none
2.19.5 x86_64

"build_cpu"
2.19.4 i386
2.19.5 x86_64

"host_cpu" has the same result as the "build_cpu"

I don't know is there some wrong with my system or it's a bug of the configure script.