Bash on ubuntu on windows cannot build

[LGinC]

[INFO ] Installing final compiler [INFO ] Installing final compiler: done in 399.41s (at 67:36) [INFO ] ================================================================= [INFO ] Installing cross-gdb [ERROR] configure: error: expat is missing or unusable [ERROR] make[2]: *** [configure-gdb] Error 1 [ERROR] make[1]: *** [all] Error 2 [ERROR] [ERROR] >> [ERROR] >> Build failed in step 'Installing cross-gdb' [ERROR] >> called in step '(top-level)' [ERROR] >> [ERROR] >> Error happened in: CT_DoExecLog[scripts/functions@257] [ERROR] >> called from: do_debug_gdb_build[scripts/build/debug/300-gdb.sh@174] [ERROR] >> called from: do_debug[scripts/build/debug.sh@35] [ERROR] >> called from: main[scripts/crosstool-NG.sh@638] [ERROR] >> [ERROR] >> For more info on this error, look at the file: 'build.log' [ERROR] >> There is a list of known issues, some with workarounds, in: [ERROR] >> 'share/doc/crosstool-ng/ct-ng.1.20.0/B - Known issues.txt' [ERROR] [ERROR] (elapsed: 72:28.46) [72:31] / ct-ng:148: recipe for target 'build' failed make: *** [build] Error 2

when I execute "./ct-ng build"

[jcmvbkbc]

error: expat is missing or unusable

Do you have development package for expat installed?