% cabal build
Resolving dependencies...
Build profile: -w ghc-8.10.5 -O1
In order, the following will be built (use -v for more details):
 - network-3.1.2.1 (lib:network) (first run)
Configuring network-3.1.2.1...
configure: WARNING: unrecognized options: --with-compiler
checking build system type... x86_64-apple-darwin19.6.0
checking host system type... x86_64-apple-darwin19.6.0
checking for gcc... /usr/bin/gcc
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 the compiler supports GNU C... yes
checking whether /usr/bin/gcc accepts -g... yes
checking for /usr/bin/gcc option to enable C11 features... none needed
checking for an ANSI C-conforming const... yes
checking for stdio.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for strings.h... yes
checking for sys/stat.h... yes
checking for sys/types.h... yes
checking for unistd.h... yes
checking for limits.h... yes
checking for stdlib.h... (cached) yes
checking for unistd.h... (cached) yes
checking for sys/types.h... (cached) yes
checking for fcntl.h... yes
checking for sys/uio.h... yes
checking for sys/socket.h... yes
checking for netinet/in.h... yes
checking for netinet/tcp.h... yes
checking for sys/un.h... yes
checking for arpa/inet.h... yes
checking for netdb.h... yes
checking for net/if.h... yes
checking for netioapi.h... no
checking for struct ucred... no
checking for gai_strerror... yes
checking for gethostent... yes
checking for accept4... no
checking for getpeereid... yes
checking for /usr/bin/gcc options needed to detect all undeclared functions... none needed
checking whether AI_ADDRCONFIG is declared... yes
checking whether AI_ALL is declared... yes
checking whether AI_NUMERICSERV is declared... yes
checking whether AI_V4MAPPED is declared... yes
checking whether IPV6_V6ONLY is declared... yes
checking whether IPPROTO_IP is declared... yes
checking whether IPPROTO_TCP is declared... yes
checking whether IPPROTO_IPV6 is declared... yes
checking whether SO_PEERCRED is declared... no
checking for struct msghdr.msg_control... yes
checking for struct msghdr.msg_accrights... no
checking for struct sockaddr.sa_len... yes
configure: creating ./network.buildinfo
configure: creating ./config.status
config.status: creating include/HsNetworkConfig.h
configure: WARNING: unrecognized options: --with-compiler
Preprocessing library for network-3.1.2.1..

 % clang --version
Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: x86_64-apple-darwin19.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin