Created attachment 1512902 [details]
minimal reproducing C++ example

Description of problem:
When compiling a program that calls std::from_chars() clang++ cannot resolve the symbol __muloti4 during linking.

Version-Release number of selected component (if applicable):
clang-7.0.0-2.fc29.x86_64

How reproducible:
always

Steps to Reproduce:
1. get attached minimal example
2. clang++ -Wall  tochars_clang_fail.cc -o tochars
3. ./tochars 123

Actual results:
/usr/bin/ld: /tmp/tochars_clang_fail-e603f8.o: in function `bool std::__detail::__raise_and_add<unsigned long>(unsigned long&, int, unsigned char)':
tochars_clang_fail.cc:(.text._ZNSt8__detail15__raise_and_addImEEbRT_ih[_ZNSt8__detail15__raise_and_addImEEbRT_ih]+0x4c): undefined reference to `__muloti4'
clang-7: error: linker command failed with exit code 1 (use -v to see invocation

Expected results:
successful compilation and as output:
123

Additional info:

Compiling with GCC works as expected:

g++ -Wall  tochars_clang_fail.cc -o tochars

Linking with libc++ also does work:

clang++ -Wall -stdlib=libc++  tochars_clang_fail.cc -o tochars