错误现象：
cygwin下ct-ng build去编译crosstool-ng出现：
CLi@PC-CLI-1 ~/develop/crosstool-ng/crosstool-ng-1.18.0_build
$ ct-ng build
......
[INFO ] =================================================================
[INFO ] Installing pass-1 core C compiler
[EXTRA] Configuring gcc
[EXTRA] Building gcc
[ERROR] make[3]: *** [libgcc/./_powisf2.o] Error 1
[ERROR] make[3]: *** [libgcc/./_powidf2.o] Error 1
[ERROR] make[2]: *** [stmp-multilib] Error 2
[ERROR] make[1]: *** [all-gcc] Error 2
......
对应build.log中的详细内容为：
[ALL ] /home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1/./gcc/xgcc -B/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1/./gcc/ -B/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/buildtools/arm-xscale-linux-gnueabi/bin/ -B/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/buildtools/arm-xscale-linux-gnueabi/lib/ -isystem /home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/buildtools/arm-xscale-linux-gnueabi/include -isystem /home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/buildtools/arm-xscale-linux-gnueabi/sys-include -O2 -g -Os -DIN_GCC -DCROSS_COMPILE -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem ./include -fPIC -g -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -Dinhibit_libc -I. -I. -I/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc -I/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc/. -I/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc/../include -I/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc/../libcpp/include -I/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc/../libdecnumber -I../libdecnumber -DL_powixf2 -c /home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/src/gcc-4.2.2/gcc/libgcc2.c -o libgcc/./_powixf2.o
[ALL ] /tmp/cc7Xh6xp.s: Assembler messages:
[ALL ] /tmp/cc7Xh6xp.s:21: Error: selected processor does not support ARM mode `fmsr s14,r0'
[ALL ] /tmp/cc7Xh6xp.s:27: Error: selected processor does not support ARM mode `flds s15,.L16'
[ALL ] /tmp/cc7Xh6xp.s:28: Error: selected processor does not support ARM mode `fcpyseq s13,s15'
[ALL ] /tmp/cc7Xh6xp.s:29: Error: selected processor does not support ARM mode `fcpysne s13,s14'
[ALL ] /tmp/cc7Xh6xp.s:39: Error: selected processor does not support ARM mode `fmuls s14,s14,s14'
[ALL ] /tmp/cc7Xh6xp.s:41: Error: selected processor does not support ARM mode `fmulsne s13,s13,s14'
[ALL ] /tmp/cc7Xh6xp.s:49: Error: selected processor does not support ARM mode `fldslt s15,.L16'
[ALL ] /tmp/cc7Xh6xp.s:50: Error: selected processor does not support ARM mode `fdivslt s13,s15,s13'
[ALL ] /tmp/cc7Xh6xp.s:52: Error: selected processor does not support ARM mode `fmrs r0,s13'
[ALL ] libgcc.mk:223: recipe for target `libgcc/./_powisf2.o' failed
[ERROR] make[3]: *** [libgcc/./_powisf2.o] Error 1
[ALL ] make[3]: *** Waiting for unfinished jobs....
[ALL ] /tmp/ccSq3fkb.s: Assembler messages:
[ALL ] /tmp/ccSq3fkb.s:21: Error: selected processor does not support ARM mode `fmdrr d6,r0,r1'
[ALL ] /tmp/ccSq3fkb.s:23: Error: selected processor does not support ARM mode `fldd d7,.L16'
[ALL ] /tmp/ccSq3fkb.s:29: Error: selected processor does not support ARM mode `fcpydeq d5,d7'
[ALL ] /tmp/ccSq3fkb.s:30: Error: selected processor does not support ARM mode `fcpydne d5,d6'
[ALL ] /tmp/ccSq3fkb.s:40: Error: selected processor does not support ARM mode `fmuld d6,d6,d6'
[ALL ] /tmp/ccSq3fkb.s:42: Error: selected processor does not support ARM mode `fmuldne d5,d5,d6'
[ALL ] /tmp/ccSq3fkb.s:50: Error: selected processor does not support ARM mode `flddlt d7,.L16'
[ALL ] /tmp/ccSq3fkb.s:51: Error: selected processor does not support ARM mode `fdivdlt d5,d7,d5'
[ALL ] /tmp/ccSq3fkb.s:54: Error: selected processor does not support ARM mode `fmrrd r0,r1,d5'
[ALL ] libgcc.mk:226: recipe for target `libgcc/./_powidf2.o' failed
[ERROR] make[3]: *** [libgcc/./_powidf2.o] Error 1
[ALL ] make[4]: `crtend.o' is up to date.
[ALL ] make[4]: `crtbeginS.o' is up to date.
[ALL ] make[4]: `crtendS.o' is up to date.
[ALL ] make[4]: `crtbeginT.o' is up to date.
[ALL ] make[4]: Leaving directory `/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1/gcc'
[ALL ] make[3]: Leaving directory `/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1/gcc'
[ALL ] Makefile:1540: recipe for target `stmp-multilib' failed
[ERROR] make[2]: *** [stmp-multilib] Error 2
[ALL ] rm gcc.pod
[ALL ] make[2]: Leaving directory `/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1/gcc'
[ALL ] Makefile:4314: recipe for target `all-gcc' failed
[ERROR] make[1]: *** [all-gcc] Error 2
[ALL ] make[1]: Leaving directory `/home/CLi/develop/crosstool-ng/crosstool-ng-1.18.0_build/.build/arm-xscale-linux-gnueabi/build/build-cc-core-pass-1'
[ERROR]
[ERROR] >>
[ERROR] >> Build failed in step 'Installing pass-1 core C compiler'
[ERROR] >> called in step '(top-level)'
原因：
至今未知
感觉好像是版本不兼容之类的问题。
解决办法：
后来是把gcc从当前的4.2.2，换成了4.6.0，就可以避免此问题了。
详见：
 |  |  |
| 5.2.1.2. Build failed in step ‘Extracting and patching toolchain components’，in function ‘CT_DoExecLog’ (line unknown, sorry) |  | 5.2.1.4. .build/arm-xscale-linux-gnueabi/buildtools/include/cloog/ppl_backend.h:54: undefined reference to `_ppl_finalize' |
