Disambiguate the reference to remquo on Windows

For #85606

This is to fix an overload ambiguity error that occur because the
C/C++ types double and long double are typealias to each other in
Swift on Windows and the system C++ header cmath.h defines a remquo
function overload for long double which conflicts with the one in the
C header corecrt_math.h in Swift.

Author: hjyamauchi

stdlib/public/Platform/tgmath.swift.gyb

@@ -295,7 +295,11 @@ public func lgamma(_ x: ${T}) -> (${T}, Int) {
 @_transparent
 public func remquo(_ x: ${T}, _ y: ${T}) -> (${T}, Int) {
   var quo = Int32(0)
+#if !os(Windows)
   let rem = unsafe remquo${f}(${CT}(x), ${CT}(y), &quo)
+#else
+  let rem = unsafe corecrt.remquo${f}(${CT}(x), ${CT}(y), &quo)
+#endif
   return (${T}(rem), Int(quo))
 }
 %  if T == 'Float80':

test/ScanDependencies/win-crt-explicit-cxx.swift

@@ -0,0 +1,54 @@
+// REQUIRES: OS=windows-msvc
+
+// Test building the CRT module with C++ interop enabled on Windows
+
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test \
+// RUN:   -module-cache-path %t/clang-module-cache -disable-objc-interop \
+// RUN:   -cxx-interoperability-mode=default \
+// RUN:   -parse-stdlib -module-load-mode prefer-serialized \
+// RUN:   %t/Test.swift -o %t/deps.json -I %t 2>&1
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SAL > %t/SAL.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:vcruntime > %t/vcruntime.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/SwiftShims.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json Swift > %t/Swift.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_Builtin_stddef > %t/_Builtin_stddef.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:corecrt > %t/corecrt.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:std_config > %t/std_config.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_float > %t/_float.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_fenv > %t/_fenv.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_stdlib > %t/_stdlib.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_malloc > %t/_malloc.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_Builtin_intrinsics > %t/_Builtin_intrinsics.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:ucrt > %t/ucrt.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:std > %t/std.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:_complex > %t/_complex.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftOverlayShims > %t/SwiftOverlayShims.cmd
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json CRT > %t/CRT.cmd
+
+// Remove the candidate module file flag to force building from the swiftinterface file.
+// RUN: cat %t/CRT.cmd | sed '/candidate-module-file/d; /CRT.swiftmodule.*swiftmodule/d' > %t/CRT.mod.cmd
+
+// RUN: %swift_frontend_plain @%t/SAL.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/vcruntime.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/SwiftShims.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/Swift.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_Builtin_stddef.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/corecrt.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/std_config.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_float.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_fenv.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_stdlib.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_malloc.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_Builtin_intrinsics.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/ucrt.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/std.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/_complex.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/SwiftOverlayShims.cmd 2>&1
+// RUN: %swift_frontend_plain @%t/CRT.mod.cmd 2>&1
+
+//--- Test.swift
+import CRT
+