clang-format --version prints nothing. Its exit code is 127.

This has worked but I haven't used it for at least a few weeks. No idea how many packages I've updated since.

I reinstalled all packages whose name contains "clang". No change.

clang-format --version || echo $?
127

strace clang-format
--- Process 26680 created
--- Process 26680 loaded C:\Windows\System32\ntdll.dll at 00007ffc10470000
--- Process 26680 loaded C:\Windows\System32\kernel32.dll at 00007ffc0f190000
--- Process 26680 loaded C:\Windows\System32\KernelBase.dll at 00007ffc0e1a0000
--- Process 26680 thread 3632 created
--- Process 26680 thread 15012 created
--- Process 26680 thread 12200 created
--- Process 26680 loaded C:\cygwin64\bin\cygwin1.dll at 00007ffb998a0000
--- Process 26680 loaded C:\cygwin64\bin\cygstdc++-6.dll at 00000003eef90000
--- Process 26680 loaded C:\cygwin64\bin\cygclangBasic-8.dll at 00000003f90b0000
--- Process 26680 loaded C:\cygwin64\bin\cygLLVMSupport-8.dll at 00000003fc200000
--- Process 26680 loaded C:\cygwin64\bin\cygclangFormat-8.dll at 00000003f87d0000
--- Process 26680 loaded C:\cygwin64\bin\cygclangToolingCore-8.dll at 00000003f73b0000
--- Process 26680 loaded C:\cygwin64\bin\cygclangRewrite-8.dll at 00000003f83d0000
--- Process 26680 loaded C:\cygwin64\bin\cyggcc_s-seh-1.dll at 00000003f6460000
--- Process 26680 loaded C:\cygwin64\bin\cygncursesw-10.dll at 00000003f0170000
--- Process 26680 loaded C:\cygwin64\bin\cygLLVMCore-8.dll at 00000003fe330000
--- Process 26680 loaded C:\cygwin64\bin\cygLLVMMC-8.dll at 00000003fd740000
--- Process 26680 loaded C:\cygwin64\bin\cygz.dll at 00000003ee480000
--- Process 26680 loaded C:\cygwin64\bin\cygLLVMDemangle-8.dll at 00000003fe090000
--- Process 26680 loaded C:\cygwin64\bin\cygclangToolingInclusions-8.dll at 00000003f7390000
--- Process 26680 loaded C:\cygwin64\bin\cygclangLex-8.dll at 00000003f84f0000
--- Process 26680 loaded C:\cygwin64\bin\cygclangAST-8.dll at 00000003f9490000
--- Process 26680 loaded C:\cygwin64\bin\cygclangLex-8.dll at 0000000000600000
--- Process 26680 unloaded DLL at 0000000000600000
--- Process 26680 loaded C:\cygwin64\bin\cygLLVMBinaryFormat-8.dll at 00000003fea90000

Then I see a pop-up that says:

The procedure entry point _alloca could not be located in the dynamic link library C:\cygwin64\bin\cygLLVMSupport-8.dll

: cygcheck $(whence clang-format)
C:\cygwin64\bin\clang-format.exe
  C:\cygwin64\bin\cygwin1.dll
    C:\windows\system32\KERNEL32.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-rtlsupport-l1-1-0.dll
      C:\windows\system32\ntdll.dll
      C:\windows\system32\KERNELBASE.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-processthreads-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-processthreads-l1-1-1.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-heap-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-memory-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-handle-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-synch-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-synch-l1-2-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-file-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-file-l1-2-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-namedpipe-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-datetime-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-sysinfo-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-timezone-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-localization-l1-2-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-processenvironment-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-string-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-debug-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-errorhandling-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-util-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-profile-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-file-l2-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-console-l1-1-0.dll
      C:\Program Files\Amazon Corretto\jdk11.0.16_9\bin\api-ms-win-core-console-l1-2-0.dll
  C:\cygwin64\bin\cygstdc++-6.dll
    C:\cygwin64\bin\cyggcc_s-seh-1.dll
  C:\cygwin64\bin\cygLLVMSupport-8.dll
    C:\cygwin64\bin\cygncursesw-10.dll
    C:\cygwin64\bin\cygz.dll
    C:\cygwin64\bin\cygLLVMDemangle-8.dll
  C:\cygwin64\bin\cygclangBasic-8.dll
    C:\cygwin64\bin\cygLLVMCore-8.dll
      C:\cygwin64\bin\cygLLVMBinaryFormat-8.dll
    C:\cygwin64\bin\cygLLVMMC-8.dll
  C:\cygwin64\bin\cygclangFormat-8.dll
    C:\cygwin64\bin\cygclangLex-8.dll
    C:\cygwin64\bin\cygclangToolingCore-8.dll
      C:\cygwin64\bin\cygclangAST-8.dll
      C:\cygwin64\bin\cygclangRewrite-8.dll
    C:\cygwin64\bin\cygclangToolingInclusions-8.dll