Hello all, I am having difficulty building Python with `--with-lto` on macOS 10.14.5. With a clean checkout of the CPython source at the tagged release for 3.7.4, I ran:
$ ./configure --prefix=/opt/python3.7.4 --enable-optimizations --enable-ipv6 --with-lto --with-openssl=$(brew --prefix openssl) CC=clang checking for git... found checking build system type... x86_64-apple-darwin18.6.0 checking host system type... x86_64-apple-darwin18.6.0 checking for python3.7... python3.7 checking for --enable-universalsdk... no checking for --with-universal-archs... no checking MACHDEP... checking for --without-gcc... no checking for --with-icc... no checking for gcc... clang checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether clang accepts -g... yes checking for clang option to accept ISO C89... none needed checking how to run the C preprocessor... clang -E checking for grep that handles long lines and -e... /usr/bin/grep checking for a sed that does not truncate output... /usr/bin/sed checking for --with-cxx-main=<compiler>... no checking for clang++... no configure: By default, distutils will build C++ extension modules with "clang++". If this is not intended, then set CXX on the configure command line. checking for the platform triplet based on compiler characteristics... darwin checking for -Wl,--no-as-needed... no checking for egrep... /usr/bin/grep -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking minix/config.h usability... no checking minix/config.h presence... no checking for minix/config.h... no checking whether it is safe to define __EXTENSIONS__... yes checking for the Android API level... not Android checking for --with-suffix... checking for case-insensitive build directory... yes checking LIBRARY... libpython$(VERSION)$(ABIFLAGS).a checking LINKCC... $(PURIFY) $(MAINCC) checking for GNU ld... no checking for --enable-shared... no checking for --enable-profiling... no checking LDLIBRARY... libpython$(VERSION)$(ABIFLAGS).a checking for ar... ar checking for readelf... no checking for a BSD-compatible install... /usr/local/bin/ginstall -c checking for a thread-safe mkdir -p... /usr/local/bin/gmkdir -p checking for --with-pydebug... no checking for --with-assertions... no checking for --enable-optimizations... yes checking for --with-lto... yes checking target system type... x86_64-apple-darwin18.6.0 checking for -llvm-ar... no checking for llvm-ar... '' configure: error: llvm-ar is required for a --with-lto build with clang but could not be found. If I change the command to `... CC=cc` configuration appears to happen normally. On my version of macOS, cc is a symlink to clang. Why is this happening? What should I be doing differently to explicitly specify clang as my compiler? Thank you, Scott Colby -- https://mail.python.org/mailman/listinfo/python-list
