[libmicrohttpd] macOS build failure for libmicrohttpd 0.9.56

[ilove zfs]

Full build log: https://gist.github.com/ilovezfs/d43a15376aef661fcb91ee145f7a9841

The error is

libtool: compile:  /usr/bin/clang -DHAVE_CONFIG_H -I. -I../.. -I../../src/include -I../../src/microhttpd -DBUILDING_MHD_LIB=1 -F/usr/local/Frameworks -fvisibility=hidden -pthread -no-cpp-precomp -fno-common -Os -w -pipe -march=native -mmacosx-version-min=10.11 -fno-strict-aliasing -c mhd_str.c  -fno-common -DPIC -o .libs/libmicrohttpd_la-mhd_str.o
mhd_str.c:721:47: error: use of undeclared identifier 'todigitvalue'; did you mean 'toxdigitvalue'?
                              toxdigitvalue : todigitvalue;
                                              ^~~~~~~~~~~~
                                              toxdigitvalue
mhd_str.c:191:1: note: 'toxdigitvalue' declared here
toxdigitvalue (char c)
^
1 error generated.
make[2]: *** [libmicrohttpd_la-mhd_str.lo] Error 1
make[1]: *** [install-recursive] Error 1
make: *** [install-recursive] Error 1

Ref: https://github.com/Homebrew/homebrew-core/pull/21032