openssl3: build failure on macOS 10.8

[mascguy (Christopher Nielsen)]

I'm seeing the following build failure on my macOS 10.8 VM, with Xcode/CLT 5.1.1:

info:build /usr/bin/clang  -I. -Icrypto -Iinclude -Iproviders/implementations/include -Iproviders/common/include  -DMD5_ASM -DOPENSSL_BN_ASM_GF2m -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_CPUID_OBJ -DOPENSSL_IA32_SSE2 -fPIC -arch x86_64 -pipe -Os -arch x86_64 -DL_ENDIAN -DOPENSSL_PIC -DOPENSSLDIR="\"/opt/local/libexec/openssl3/etc/openssl\"" -DENGINESDIR="\"/opt/local/libexec/openssl3/lib/engines-3\"" -DMODULESDIR="\"/opt/local/libexec/openssl3/lib/ossl-modules\"" -D_REENTRANT -DOPENSSL_BUILDING_OPENSSL -DZLIB -DNDEBUG -I/opt/local/include -MMD -MF crypto/bn/liblegacy-lib-rsaz_exp.d.tmp -MT crypto/bn/liblegacy-lib-rsaz_exp.o -c -o crypto/bn/liblegacy-lib-rsaz_exp.o crypto/bn/rsaz_exp.c
:info:build crypto/bn/rsaz-x86_64.s:418:2: error: invalid instruction mnemonic 'adcxq'
:info:build  adcxq %rcx,%r9
:info:build  ^~~~~
[...more of the same...]

:info:build  adcxq %r/usr/bin/clang  -I. -Icrypto -Iinclude -Iproviders/implementations/include -Iproviders/common/include  -DMD5_ASM -DOPENSSL_BN_ASM_GF2m -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_CPUID_OBJ -DOPENSSL_IA32_SSE2 -fPIC -arch x86_64 -pipe -Os -arch x86_64 -DL_ENDIAN -DOPENSSL_PIC -DOPENSSLDIR="\"/opt/local/libexec/openssl3/etc/openssl\"" -DENGINESDIR="\"/opt/local/libexec/openssl3/lib/engines-3\"" -DMODULESDIR="\"/opt/local/libexec/openssl3/lib/ossl-modules\"" -D_REENTRANT -DOPENSSL_BUILDING_OPENSSL -DZLIB -DNDEBUG -I/opt/local/include -MMD -MF crypto/bn/liblegacy-lib-rsaz_exp_x2.d.tmp -MT crypto/bn/liblegacy-lib-rsaz_exp_x2.o -c -o crypto/bn/liblegacy-lib-rsaz_exp_x2.o crypto/bn/rsaz_exp_x2.c
:info:build crypto/bn/rsaz-x86_64.s:1092:2: error: invalid instruction mnemonic 'adcxq'
:info:build  adcxq %rbx,%r13
:info:build  ^~~~~
[...more of the same...]

Note that updating the portfile to blacklist older Xcode clangs solves the issue.

However, given that our 10.8 buildbot is running Xcode 5.1.1 as well - and builds succeed there - thus far I've chalked it up to quirks in my particular 10.8 setup.

Also of note, this port builds successfully on every one of my other macOS VMs - including 10.6 and 10.7, as well as 10.9 through 10.15. It also builds successfully on my physical installations, for 10.12 through 10.15.