See https://trac.macports.org/ticket/62428 for the same issue. --- configure.ac.orig 2020-10-09 06:51:29.000000000 -0700 +++ configure.ac 2021-03-26 21:00:44.000000000 -0700 @@ -9,6 +9,7 @@ AC_CANONICAL_HOST AC_PROG_CC +AC_PROG_CPP AM_PROG_CC_C_O AC_PROG_LIBTOOL PKG_PROG_PKG_CONFIG