ADDITIONAL SYSTEM INFORMATION :
Windows 10 64-bit
OpenJDK 11.0.10 64-bit
Can be reproduced while building OpenJFX 15.0.2 and master (17)

A DESCRIPTION OF THE PROBLEM :
Hello everyone,

I was hoping you could help me to figure out why I can't build webkit on my Windows 10 machine. I think I did everything according to the instructions on https://wiki.openjdk.java.net/display/OpenJFX/Building+OpenJFX, but it still doesn't work.

It seems that by some reason it can't execute cygpath command from a perl script:

> Task :web:compileNativeWin
Caching disabled for task ':web:compileNativeWin' because:
  Build cache is disabled
Task ':web:compileNativeWin' is not up-to-date because:
  Task has not declared any outputs despite executing actions.
Starting process 'command 'perl''. Working directory: C:\openjfx-src\jfx\modules\javafx.web\build\win Command: perl C:\openjfx-src\jfx\modules\javafx.web/src/main/native/Tools/Scripts/set-webkit-configuration --Release
Successfully started process 'command 'perl''
Starting process 'command 'perl''. Working directory: C:\openjfx-src\jfx\modules\javafx.web\build\win Command: perl C:\openjfx-src\jfx\modules\javafx.web/src/main/native/Tools/Scripts/build-webkit --java --icu-unicode --64-bit --no-experimental-features --cmakeargs= -DEN
ABLE_TOOLS=1 -DCMAKE_C_COMPILER='C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.10.25017/bin/Hostx64/x64/cl.exe' -DJAVAFX_RELEASE_VERSION=17
Successfully started process 'command 'perl''
sh: cygpath: command not found
sh: cygpath: command not found
Can't exec "uname": No such file or directory at /cygdrive/c/openjfx-src/jfx/modules/javafx.web/src/main/native/Tools/Scripts/webkitdirs.pm line 366.
sh: cygpath: command not found
+ cmake -DPORT="Java" -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_BUILD_TYPE=Release -G Ninja -DSHOW_BINDINGS_GENERATION_PROGRESS=1 -DDEVELOPER_MODE=ON -DENABLE_TOOLS=1 -DCMAKE_C_COMPILER='C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.10
.25017/bin/Hostx64/x64/cl.exe' -DJAVAFX_RELEASE_VERSION=17 ""
CMake Error: The source directory "C:/cygwin64/Release" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.

> Task :web:compileNativeWin FAILED
:web:compileNativeWin (Thread[Execution worker for ':' Thread 2,5,main]) completed. Took 21.571 secs.

FAILURE: Build failed with an exception.

* Where:
Build file 'C:\openjfx-src\jfx\build.gradle' line: 3453

* What went wrong:
Execution failed for task ':web:compileNativeWin'.
> Process 'command 'perl'' finished with non-zero exit value 1

I can run fine cygpath in the terminal:

> which cygpath
/usr/bin/cygpath

> cygpath -w "/cygdrive/c/Windows"
C:\Windows

Has anyone seen such an issue? How could I debug and fix it?

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Follow the instructions from https://wiki.openjdk.java.net/display/OpenJFX/Building+OpenJFX while building on Windows 10.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Success build.
ACTUAL -
Failed build with error:
sh: cygpath: command not found

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not required, build issue
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FREQUENCY : always