Build error on 10.7 with Apple Clang: error: invalid instruction mnemonic 'cvttss2sil'

[barracuda156]

[10/23] /opt/local/bin/gfortran-mp-12 -Ilibfson.dylib.p -I. -I../josephalevin-fson-16731d9 -fdiagnostics-color=always -Wall -O0 -g -pipe -Os -m64 -Wno-maybe-uninitialized -Jlibfson.dylib.p -o libfson.dylib.p/src_fson_path_m.f90.o -c ../josephalevin-fson-16731d9/src/fson_path_m.f90
FAILED: libfson.dylib.p/src_fson_path_m.f90.o libfson.dylib.p/fson_path_m.mod 
/opt/local/bin/gfortran-mp-12 -Ilibfson.dylib.p -I. -I../josephalevin-fson-16731d9 -fdiagnostics-color=always -Wall -O0 -g -pipe -Os -m64 -Wno-maybe-uninitialized -Jlibfson.dylib.p -o libfson.dylib.p/src_fson_path_m.f90.o -c ../josephalevin-fson-16731d9/src/fson_path_m.f90
clang: warning: argument unused during compilation: '-I libfson.dylib.p'
clang: warning: argument unused during compilation: '-I .'
clang: warning: argument unused during compilation: '-I ../josephalevin-fson-16731d9'
<stdin>:3356:2: error: invalid instruction mnemonic 'cvttss2sil'
        cvttss2sil      32(%rax), %eax
        ^~~~~~~~~~
ninja: build stopped: subcommand failed.

Log: https://build.macports.org/builders/ports-10.7_x86_64-builder/builds/130836/steps/install-port/logs/stdio
Elsewhere it builds fine.