__builtin / OS X / gcc 4.2.1

[textbrowser]

The __builtin_cpu_supports function is not defined.

cc -g -Wall -Wextra -Wno-unused-parameter -DNTRU_DETECT_SIMD -O2  -c -fPIC src/hash.c -o src/hash.o
src/hash.c:83:9: error: use of unknown builtin '__builtin_cpu_supports' [-Wimplicit-function-declaration]
    if (__builtin_cpu_supports("ssse3") || __builtin_cpu_supports("avx2")) {

https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/X86-Built-in-Functions.html

[masonbrothers]

I was able to get it to build by using gcc instead of clang. I installed gcc with Homebrew:
brew install gcc

The makefile respects the CC environment variable.

I believe gcc is a symbolic link by default to clang on macOS (or this is at least true after Xcode has been installed). To get around this, I specified the version of gcc that I was using. The versions that bash knows of can be seen by typing in gcc in the console followed by two tabs.

On my computer, I had gcc-7.

To build I used:

export CC=gcc-7
make

Alternatively, I think that gcc could be added to the path before the symbolic link to clang.