Support "C-unwind" ABI

Closes #864

tests/expectations/abi_string.c

@@ -0,0 +1,8 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+void c(void);
+
+void c_unwind(void);

tests/expectations/abi_string.compat.c

@@ -0,0 +1,16 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+void c(void);
+
+void c_unwind(void);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus

tests/expectations/abi_string.cpp

@@ -0,0 +1,13 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <ostream>
+#include <new>
+
+extern "C" {
+
+void c();
+
+void c_unwind();
+
+} // extern "C"

tests/expectations/abi_string.pyx

@@ -0,0 +1,11 @@
+from libc.stdint cimport int8_t, int16_t, int32_t, int64_t, intptr_t
+from libc.stdint cimport uint8_t, uint16_t, uint32_t, uint64_t, uintptr_t
+cdef extern from *:
+  ctypedef bint bool
+  ctypedef struct va_list
+
+cdef extern from *:
+
+  void c();
+
+  void c_unwind();

tests/rust/abi_string.rs

@@ -0,0 +1,5 @@
+#[no_mangle]
+pub extern "C" fn c() {}
+
+#[no_mangle]
+pub extern "C-unwind" fn c_unwind() {}