Add Gentoo Portage host configuration

env/codex-lowmem.conf

@@ -0,0 +1,20 @@
+# /etc/portage/env/codex-lowmem.conf
+# Alternative compiler configuration (Clang/LLVM) to mitigate low-memory compilation issues
+
+# 1. Alternative compiler: Clang/LLVM toolchain
+CC="clang"
+CXX="clang++"
+CPP="clang-cpp"
+AR="llvm-ar"
+NM="llvm-nm"
+RANLIB="llvm-ranlib"
+
+# 2. Parallel jobs reduction: limit make to 1 job to prevent RAM exhaustion
+MAKEOPTS="-j1"
+
+# 3. Memory-efficient linker: use LLD and release unneeded memory pages
+LDFLAGS="${LDFLAGS} -fuse-ld=lld -Wl,--no-keep-memory"
+
+# 4. Memory-efficient LTO: use ThinLTO instead of full monolithic LTO
+CFLAGS="${CFLAGS} -flto=thin"
+CXXFLAGS="${CXXFLAGS} -flto=thin"