dvisvgm-2.12 (clipper.cpp) fails to be built with /usr/include/c++/v1/cmath

[ShugoSUWAZONO]

/usr/bin/clang++ -std=gnu++11 -DHAVE_CONFIG_H -I. -I../..   -I/opt/local/include -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX11.sdk -Wall -pipe -Os -stdlib=libc++ -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX11.sdk -arch x86_64 -Wno-mismatched-tags -MT clipper.o -MD -MP -MF $depbase.Tpo -c -o clipper.o clipper.cpp &&\
mv -f $depbase.Tpo $depbase.Po
In file included from clipper.cpp:42:
/Library/Developer/CommandLineTools/SDKs/MacOSX11.sdk/usr/include/c++/v1/cmath:321:9: error: no member named 'signbit' in the global namespace
using ::signbit;
       ~~^

...similar error continues for ::fpclassify, ::isfinite, ::isinf, ::isnan, ::isnormal, ::isgreater, ::isgreat, ...

13 errors generated.

[ShugoSUWAZONO]

error log file generated while dvisvgm-2.12 install

[michaelld (Michael Dickens)]

OP reports on the MP list:

I found the reason causing this problem. That was my mistake to made some symbolic links from several header files (stdio.h etc)
from
/Library/Developer/CommandLineTools/SDKs/MacOSX11.sdk/usr/include/
to
/opt/local/include/
After deleting those symbolic links, the upgrade (sudo port install dvisvgm) was successfully finished.

Hence I'm closing.