"Unknown option --exist" message when building qemu

[Guenter Roeck]

Hi,

when building qemu, I keep seeing the following message.

Unknown option --exist

This was introduced with commit 3a67848134d0 ("configure: Enable test and libs 
for zstd").
If I replace "--exist" with "--exists", on a system with libzstd-dev installed, 
I get
a number of error messages.

migration/multifd-zstd.c:125:9: error: unknown type name ‘ZSTD_EndDirective’; 
did you mean ‘ZSTD_DDict’?
migration/multifd-zstd.c:125:35: error: ‘ZSTD_e_continue’ undeclared
migration/multifd-zstd.c:128:21: error: ‘ZSTD_e_flush’ undeclared
migration/multifd-zstd.c:143:19: error: implicit declaration of function 
‘ZSTD_compressStream2’
migration/multifd-zstd.c:143:19: error: nested extern declaration of 
‘ZSTD_compressStream2’

Any idea, anyone, what might be wrong ?

Thanks,
Guenter