enblend: builds fail for 10.13: clang 9.0 crash

[mascguy (Christopher Nielsen)]

While this port builds locally for 10.13 without error (at least for yours truly), it consistently fails on the buildbot with the following:

/usr/bin/clang++ -DHAVE_CONFIG_H -I. -I..   -I/opt/local/libexec/boost/1.76/include -I/opt/local/include -DENBLEND_SOURCE
-D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -I../src/dynamic_loader -I../src/layer_selection -D_THREAD_SAFE -I/opt/local/include/OpenEXR -pipe
-I/opt/local/libexec/boost/1.76/include -Os -std=c++11 -stdlib=libc++ -arch x86_64 -O2 -DNDEBUG -MT enblend-enblend.o -MD -MP -MF
.deps/enblend-enblend.Tpo -c -o enblend-enblend.o `test -f 'enblend.cc' || echo './'`enblend.cc

clang: error: unable to execute command: Illegal instruction: 4
clang: error: clang frontend command failed due to signal (use -v to see invocation)
Apple LLVM version 9.1.0 (clang-902.0.39.2)
Target: x86_64-apple-darwin17.7.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

[...]

make[4]: *** [enblend-enblend.o] Error 254
make[4]: *** Waiting for unfinished jobs....
clang: error: unable to execute command: Illegal instruction: 4
clang: error: clang frontend command failed due to signal (use -v to see invocation)

[mascguy (Christopher Nielsen)]

Full build log attached, sourced from:

​https://build.macports.org/builders/ports-10.13_x86_64-builder/builds/160077/steps/install-port/logs/stdio

[Christopher Nielsen <mascguy@…>]

In 05f3bdb00f227307af5210e2c2c8d1ba1a6f7bb1/macports-ports (master):

enblend: add build dep cctools

• Naive fix, for potential assembler-related crash

See: #65694

[Christopher Nielsen <mascguy@…>]

In 3a4b8eb581a8f65aca914d31aede20898a09a943/macports-ports (master):

enblend: blacklist clang < 1000; revert cctools
See: #65694