jprt jobs that attempt to do jtreg tests fail on windows with:

( C:/jprt/products/P2/gnumake3.81/cygwin/bin/make.exe
  ALT_SLASH_JAVA=C:/jprt/slashjava
  JPRT_PRODUCT_PATH=C:/temp/jprt/P2/054442.jcoomes/testproduct/windows_i586_5.1-product
  JPRT_ARCHIVE_BUNDLE=C:/temp/jprt/P2/054442.jcoomes/bundles/windows_i586-product-c1-langtools_jtreg.zip
  langtools_jtreg )
C:/jprt/products/P2/gnumake3.81/cygwin/bin/make -C ../langtools/test jtreg
make[1]: Entering directory `/cygdrive/c/temp/jprt/P2/054442.jcoomes/source/langtools/test'
rm -f C:/temp/jprt/P2/054442.jcoomes/bundles/windows_i586-product-c1-langtools_jtreg.zip
make[1]: *** No rule to make target `C:/jprt/products/P2/jtreg4.1-latest/jtreg//bin/jtreg', needed by `check-jtreg'. Stop.
make[1]: Leaving directory `/cygdrive/c/temp/jprt/P2/054442.jcoomes/source/langtools/test'
make: *** [langtools_jtreg] Error 2

The jprt command line was:
  jprt submit -forest -noqa -nocrupdates -excludetests 'jdk_tools.*'
  -excludetargets 'linux_(arm|ppc).*' -control 'hotspot corba langtools jaxws
  jaxp jdk deploy install' -buildenv SKIP_BOOT_CYCLE=false -buildenv
  NO_DOCS=true -release jdk8

The full jprt build logs are attached.