Check for SSSE3 instructions.

These are needed for Homebrew on Linux x86_64.

Author: MikeMcQuaid

CODEOWNERS

@@ -8,4 +8,4 @@
 #
 # Note: @Homebrew/plc does not have write-access to this repository, and therefore cannot be listed in this file.
 
-docs/Support-Tiers.md  @Homebrew/tsc @MikeMcQuaid
+docs/Support-Tiers.md  @Homebrew/lead-maintainers @MikeMcQuaid

Library/Homebrew/brew.sh

@@ -654,6 +654,15 @@ then
   # Some Git versions are too old for some Homebrew functionality we rely on.
   HOMEBREW_MINIMUM_GIT_VERSION="2.14.3"
 else
+  if [[ -r "/proc/cpuinfo" ]] &&
+     [[ "${HOMEBREW_PROCESSOR}" == "x86_64" ]]
+  then
+    if ! grep -E "^(flags|Features)" /proc/cpuinfo | grep -q "ssse3"
+    then
+      odie "Homebrew's x86_64 support on Linux requires a CPU with SSSE3 support!"
+    fi
+  fi
+
   HOMEBREW_PRODUCT="${HOMEBREW_SYSTEM}brew"
   # Don't try to follow /etc/os-release
   # shellcheck disable=SC1091,SC2154

docs/Support-Tiers.md

@@ -46,7 +46,7 @@ To qualify as Tier 1, a Linux configuration must meet all of the following:
 - Using a system `glibc` version ≥ 2.35
 - Using a Linux kernel version ≥ 3.2
 - Installed in the default prefix: `/home/linuxbrew/.linuxbrew`
-- Using a supported architecture (ARM64/AArch64 or Intel x86_64)
+- Using a supported architecture (ARM64/AArch64 or Intel x86_64 with SSSE3 support)
 - Not building official packages from source (i.e. using bottles)
 - Running with `sudo` access available