Issue #7485 has been reported by drbrain (Eric Hodel).

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Bug #7485: ruby cannot build on mingw32 due to missing __sync_val_compare_and_swap
https://bugs.ruby-lang.org/issues/7485

Author: drbrain (Eric Hodel)
Status: Open
Priority: Normal
Assignee: nobu (Nobuyoshi Nakada)
Category: build
Target version: 2.0.0
ruby -v: trunk


mingw32 GCC has the other atomic builtins but not this one.  The attached patch checks for the GCC builtins used in ruby_atomic.h but not checked for by configure.


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