zstd-1.4.5 fails to compile on my CentOS 6.10 boxes. Error messages:
/tmp/ccja65az.s: Assembler messages:
/tmp/ccja65az.s:99: Error: no such instruction: `shlx %edi,%eax,%eax'
/tmp/ccja65az.s:115: Error: no such instruction: `sarx %rax,%rdx,%rdx'
/tmp/ccja65az.s:133: Error: no such instruction: `shlx %r9d,%edx,%edx'
/tmp/ccja65az.s:147: Error: no such instruction: `sarx %rax,%rdx,%rdx'
/tmp/ccja65az.s:163: Error: no such instruction: `shlx %r8d,%eax,%eax'
/tmp/ccja65az.s:181: Error: no such instruction: `sarx %rax,%rsi,%rsi'
/tmp/ccja65az.s:197: Error: no such instruction: `shlx %r8,%rsi,%rsi'
/tmp/ccja65az.s:209: Error: no such instruction: `shlx %r8,%rax,%rax'
/tmp/ccja65az.s:223: Error: no such instruction: `shrx %rax,%rcx,%rax'
/tmp/ccja65az.s:252: Error: no such instruction: `shrx %rdi,%rax,%rax'
/tmp/ccja65az.s:274: Error: no such instruction: `shlx %rdx,%rdi,%rdi'
/tmp/ccja65az.s:276: Error: no such instruction: `sarx %rsi,%r11,%rsi'
/tmp/ccja65az.s:289: Error: no such instruction: `shlx %rdx,%r8,%r8'
/tmp/ccja65az.s:291: Error: no such instruction: `sarx %rsi,%r15,%rsi'
/tmp/ccja65az.s:304: Error: no such instruction: `shlx %rdx,%rdi,%rdi'
/tmp/ccja65az.s:306: Error: no such instruction: `sarx %rcx,%r10,%rcx'
/tmp/ccja65az.s:323: Error: no such instruction: `shlx %rdx,%rcx,%rdx'
/tmp/ccja65az.s:331: Error: no such instruction: `shlx %rsi,%r12,%rdx'
/tmp/ccja65az.s:344: Error: no such instruction: `shlx %r14,%rcx,%rdi'
/tmp/ccja65az.s:354: Error: no such instruction: `shlx %r8,%rbx,%rbx'
/tmp/ccja65az.s:367: Error: no such instruction: `shrx %rdx,%rax,%rax'
/tmp/ccja65az.s:374: Error: no such instruction: `shlx %r8,%r11,%r11'
/tmp/ccja65az.s:385: Error: no such instruction: `shrx %rcx,%r11,%r11'
/tmp/ccja65az.s:390: Error: no such instruction: `shlx %r8,%r10,%r10'
/tmp/ccja65az.s:402: Error: no such instruction: `shrx %rcx,%r10,%r10'
/tmp/ccja65az.s:404: Error: no such instruction: `shlx %rdx,%rcx,%rdx'
/tmp/ccja65az.s:461: Error: no such instruction: `shrx %rdx,%rax,%rax'
/tmp/ccja65az.s:474: Error: no such instruction: `shrx %rcx,%rax,%rax'
/tmp/ccja65az.s:480: Error: no such instruction: `shlx %r14,%rcx,%rcx'
/tmp/ccja65az.s:492: Error: no such instruction: `shrx %rdx,%rax,%rax'
/tmp/ccja65az.s:499: Error: no such instruction: `shlx %r8,%rax,%rax'
/tmp/ccja65az.s:509: Error: no such instruction: `shlx %r8,%rax,%rax'
/tmp/ccja65az.s:522: Error: no such instruction: `shrx %rcx,%rax,%rcx'
make[1]: *** [compress/zstd_compress_sequences.o] Error 1
make[1]: *** Waiting for unfinished jobs....
/tmp/ccGU0SYr.s: Assembler messages:
/tmp/ccGU0SYr.s:519: Error: no such instruction: `shlx %r13,%rax,%rax'
/tmp/ccGU0SYr.s:522: Error: no such instruction: `shlx %rcx,%r13,%rcx'
/tmp/ccGU0SYr.s:525: Error: no such instruction: `shlx %r12,%rcx,%r12'
/tmp/ccGU0SYr.s:528: Error: no such instruction: `shlx %rdx,%rcx,%rcx'
/tmp/ccGU0SYr.s:544: Error: no such instruction: `shrx %rdx,%rax,%rsi'
/tmp/ccGU0SYr.s:549: Error: no such instruction: `shlx %rcx,%rax,%rax'
/tmp/ccGU0SYr.s:606: Error: no such instruction: `shlx %r12,%r10,%rsi'
/tmp/ccGU0SYr.s:614: Error: no such instruction: `shlx %r10,%rsi,%rsi'
/tmp/ccGU0SYr.s:627: Error: no such instruction: `shrx %rax,%rsi,%rsi'
make[1]: *** [compress/huf_compress.o] Error 1
make[1]: Leaving directory `/usr/local/directadmin/custombuild/zstd-1.4.5/lib'
make: *** [install] Error 2