[Issue 21083] New: Failed to compile on MacOS 10.15.3

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21083

          Issue ID: 21083
           Summary: Failed to compile on MacOS 10.15.3
           Product: D
           Version: D2
          Hardware: x86
                OS: Mac OS X
            Status: NEW
          Severity: blocker
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: scientificworld at 126.com

When I wanted to compile a "hello world" program, it showed me this:

Undefined symbols for architecture x86_64:
  "_main", referenced from:
     implicit entry/start for main executable
     (maybe you meant: __D4core6thread16_mainThreadStoreG312v,
__D4core6thread6Thread7sm_mainCQBcQBaQw )
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Error: linker exited with status 1

OS Version: MacOS 10.15.3
D Compiler Version: DMD64 D Compiler v2.093.0
Clang Version: Apple clang version 11.0.3 (clang-1103.0.32.62)

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