Hack to make C++ exceptions test work on i686-pc-windows-gnu

src/test/run-make-fulldeps/foreign-exceptions/Makefile

@@ -4,7 +4,7 @@ all: foo
 	$(call RUN,foo)
 
 foo: foo.rs $(call NATIVE_STATICLIB,foo)
-	$(RUSTC) $< -lfoo $(EXTRACXXFLAGS)
+	$(RUSTC) $< -lfoo $(EXTRARSCXXFLAGS)
 
 $(TMPDIR)/libfoo.o: foo.cpp
 	$(call COMPILE_OBJ_CXX,$@,$<)

src/test/run-make-fulldeps/foreign-exceptions/foo.rs

@@ -2,6 +2,9 @@
 // are ignored by catch_unwind. Also tests that Rust panics can unwind through
 // C++ code.
 
+// For linking libstdc++ on MinGW
+#![cfg_attr(all(windows, target_env = "gnu"), feature(static_nobundle))]
+
 #![feature(unwind_attributes)]
 
 use std::panic::{catch_unwind, AssertUnwindSafe};

src/test/run-make-fulldeps/issue-36710/Makefile

@@ -6,7 +6,7 @@ all: foo
 	$(call RUN,foo)
 
 foo: foo.rs $(call NATIVE_STATICLIB,foo)
-	$(RUSTC) $< -lfoo $(EXTRACXXFLAGS)
+	$(RUSTC) $< -lfoo $(EXTRARSCXXFLAGS)
 
 $(TMPDIR)/libfoo.o: foo.cpp
 	$(call COMPILE_OBJ_CXX,$@,$<)

src/test/run-make-fulldeps/issue-36710/foo.rs

@@ -1,5 +1,8 @@
 // Tests that linking to C++ code with global destructors works.
 
+// For linking libstdc++ on MinGW
+#![cfg_attr(all(windows, target_env = "gnu"), feature(static_nobundle))]
+
 extern { fn get() -> u32; }
 
 fn main() {

src/test/run-make-fulldeps/tools.mk

@@ -81,6 +81,22 @@ ifdef IS_MSVC
 else
 	EXTRACFLAGS := -lws2_32 -luserenv
 	EXTRACXXFLAGS := -lstdc++
+	# So this is a bit hacky: we can't use the DLL version of libstdc++ because
+	# it pulls in the DLL version of libgcc, which means that we end up with 2
+	# instances of the DW2 unwinding implementation. This is a problem on
+	# i686-pc-windows-gnu because each module (DLL/EXE) needs to register its
+	# unwind information with the unwinding implementation, and libstdc++'s
+	# __cxa_throw won't see the unwinding info we registered with our statically
+	# linked libgcc.
+	#
+	# Now, simply statically linking libstdc++ would fix this problem, except
+	# that it is compiled with the expectation that pthreads is dynamically
+	# linked as a DLL and will fail to link with a statically linked libpthread.
+	#
+	# So we end up with the following hack: we link use static-nobundle to only
+	# link the parts of libstdc++ that we actually use, which doesn't include
+	# the dependency on the pthreads DLL.
+	EXTRARSCXXFLAGS := -l static-nobundle=stdc++
 endif
 else
 ifeq ($(UNAME),Darwin)
@@ -98,6 +114,7 @@ ifeq ($(UNAME),OpenBSD)
 else
 	EXTRACFLAGS := -lm -lrt -ldl -lpthread
 	EXTRACXXFLAGS := -lstdc++
+	EXTRARSCXXFLAGS := -lstdc++
 endif
 endif
 endif