Write a minimal config.log when configuring.
--- configure.orig	2020-12-20 05:47:07.000000000 -0600
+++ configure	2020-12-20 05:48:35.000000000 -0600
@@ -216,7 +216,9 @@
 INCLUDEDIR=${INCLUDEDIR-/usr/include}
 
 rm -f conftest conftest.c
-compile="$CC $CFLAGS $CPPFLAGS $LDFLAGS $DEFS conftest.c -o conftest $LIBS >/dev/null 2>&1"
+log=config.log
+echo "$0" "$@" >$log
+compile="echo >>$log && echo configure:\$LINENO: $CC $CFLAGS $CPPFLAGS $LDFLAGS $DEFS conftest.c -o conftest $LIBS >>$log && $CC $CFLAGS $CPPFLAGS $LDFLAGS $DEFS conftest.c -o conftest $LIBS >>$log 2>&1"
 
 # Check for various header files.
 
