zstd not found if installed in non-system prefix

[Michael Kuhn]

Hi,

when specifying a non-system prefix with --with-zstd, the build fails
because the header and library cannot be found (see 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95005).

The attached patch fixes the problem and is what we use in Spack to
make GCC build with zstd support.


Best regards,
Michael
-------------- next part --------------
A non-text attachment was scrubbed...
Name: zstd.patch
Type: text/x-patch
Size: 1211 bytes
Desc: not available
URL: <https://gcc.gnu.org/pipermail/gcc-patches/attachments/20200520/5a681283/attachment.bin>