Link error, seems transient as other builds do not present this problem:
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\deflate.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\infback.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\inffast.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\inflate.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\inftrees.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\uncompr.obj"
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\obj\37amd64_Debug\pythoncore\getbuildinfo.obj"
2>LINK : fatal error LNK1104: cannot open file 'C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\amd64\python37_d.dll' [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
2>Done Building Project "C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj" (Build target(s)) -- FAILED.
1>Done Building Project "C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pcbuild.proj" (Build target(s)) -- FAILED.
Build FAILED.
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj" (Build target) (2) ->
(ClCompile target) ->
..\Modules\gcmodule.c(975): warning C4244: 'function': conversion from 'Py_ssize_t' to 'int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\ast.c(4279): warning C4244: '+=': conversion from '__int64' to 'int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(162): warning C4244: 'function': conversion from 'Py_ssize_t' to 'unsigned int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(360): warning C4267: 'function': conversion from 'size_t' to 'unsigned int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(393): warning C4267: '=': conversion from 'size_t' to 'unsigned int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(400): warning C4244: '-=': conversion from 'Py_ssize_t' to 'unsigned int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(425): warning C4244: '=': conversion from 'Py_ssize_t' to 'unsigned int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
..\Python\peephole.c(478): warning C4244: 'function': conversion from 'Py_ssize_t' to 'int', possible loss of data [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
"C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj" (Build target) (2) ->
(Link target) ->
LINK : fatal error LNK1104: cannot open file 'C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\amd64\python37_d.dll' [C:\
buildbot.python.org\3.7.kloth-win64\build\PCbuild\pythoncore.vcxproj]
8 Warning(s)
1 Error(s)