cmake HAVE_SWIFTCALL examples

swiftlang/swift Runtimes/Core/cmake/modules/CompilerSettings.cmake :25

check_source_compiles(CXX
"#if !(__has_attribute(swiftcall) && \
  __has_attribute(swift_context) && \
  __has_attribute(swift_error_result) && \
  __has_attribute(swift_indirect_result))
#error CXX compiler must support Swift calling conventions
#endif
int main(void) { return 0; }"
HAVE_SWIFTCALL)

swiftlang/swift Runtimes/Supplemental/cmake/modules/SwiftCallingConventions.cmake :4

check_source_compiles(CXX
"#if !(__has_attribute(swiftcall) && \
  __has_attribute(swift_context) && \
  __has_attribute(swift_error_result) && \
  __has_attribute(swift_indirect_result))
#error CXX compiler must support Swift calling conventions
#endif
int main(void) { return 0; }"
HAVE_SWIFTCALL)