Xcode: Detect architecture(s) using ARCHS instead of CURRENT_ARCH

Xcode 10 no longer populates `CURRENT_ARCH` with the current
architecture in shell scripts and instead uses `undefined_arch`.
Instead we must use `ARCHS`.  It lists all architectures separated by
spaces.

Fixes: #18085

Modules/CMakeCCompiler.cmake.in

@@ -15,7 +15,7 @@ set(CMAKE_C_SIMULATE_ID "@CMAKE_C_SIMULATE_ID@")
 set(CMAKE_C_SIMULATE_VERSION "@CMAKE_C_SIMULATE_VERSION@")
 @_SET_CMAKE_C_COMPILER_ARCHITECTURE_ID@
 @SET_MSVC_C_ARCHITECTURE_ID@
-@SET_CMAKE_XCODE_CURRENT_ARCH@
+@SET_CMAKE_XCODE_ARCHS@
 set(CMAKE_AR "@CMAKE_AR@")
 set(CMAKE_C_COMPILER_AR "@CMAKE_C_COMPILER_AR@")
 set(CMAKE_RANLIB "@CMAKE_RANLIB@")

Modules/CMakeCXXCompiler.cmake.in

@@ -17,7 +17,7 @@ set(CMAKE_CXX_SIMULATE_ID "@CMAKE_CXX_SIMULATE_ID@")
 set(CMAKE_CXX_SIMULATE_VERSION "@CMAKE_CXX_SIMULATE_VERSION@")
 @_SET_CMAKE_CXX_COMPILER_ARCHITECTURE_ID@
 @SET_MSVC_CXX_ARCHITECTURE_ID@
-@SET_CMAKE_XCODE_CURRENT_ARCH@
+@SET_CMAKE_XCODE_ARCHS@
 set(CMAKE_AR "@CMAKE_AR@")
 set(CMAKE_CXX_COMPILER_AR "@CMAKE_CXX_COMPILER_AR@")
 set(CMAKE_RANLIB "@CMAKE_RANLIB@")

Modules/CMakeDetermineCCompiler.cmake

@@ -183,9 +183,9 @@ if(MSVC_C_ARCHITECTURE_ID)
     "set(MSVC_C_ARCHITECTURE_ID ${MSVC_C_ARCHITECTURE_ID})")
 endif()
 
-if(CMAKE_C_XCODE_CURRENT_ARCH)
-  set(SET_CMAKE_XCODE_CURRENT_ARCH
-    "set(CMAKE_XCODE_CURRENT_ARCH ${CMAKE_C_XCODE_CURRENT_ARCH})")
+if(CMAKE_C_XCODE_ARCHS)
+  set(SET_CMAKE_XCODE_ARCHS
+    "set(CMAKE_XCODE_ARCHS \"${CMAKE_C_XCODE_ARCHS}\")")
 endif()
 
 # configure variables set in this file for fast reload later on

Modules/CMakeDetermineCXXCompiler.cmake

@@ -181,9 +181,9 @@ if(MSVC_CXX_ARCHITECTURE_ID)
     "set(MSVC_CXX_ARCHITECTURE_ID ${MSVC_CXX_ARCHITECTURE_ID})")
 endif()
 
-if(CMAKE_CXX_XCODE_CURRENT_ARCH)
-  set(SET_CMAKE_XCODE_CURRENT_ARCH
-    "set(CMAKE_XCODE_CURRENT_ARCH ${CMAKE_CXX_XCODE_CURRENT_ARCH})")
+if(CMAKE_CXX_XCODE_ARCHS)
+  set(SET_CMAKE_XCODE_ARCHS
+    "set(CMAKE_XCODE_ARCHS \"${CMAKE_CXX_XCODE_ARCHS}\")")
 endif()
 
 # configure all variables set in this file

Modules/CMakeDetermineCompilerId.cmake

@@ -121,7 +121,7 @@ function(CMAKE_DETERMINE_COMPILER_ID lang flagvar src)
   set(CMAKE_${lang}_COMPILER_ARCHITECTURE_ID "${CMAKE_${lang}_COMPILER_ARCHITECTURE_ID}" PARENT_SCOPE)
   set(MSVC_${lang}_ARCHITECTURE_ID "${MSVC_${lang}_ARCHITECTURE_ID}"
     PARENT_SCOPE)
-  set(CMAKE_${lang}_XCODE_CURRENT_ARCH "${CMAKE_${lang}_XCODE_CURRENT_ARCH}" PARENT_SCOPE)
+  set(CMAKE_${lang}_XCODE_ARCHS "${CMAKE_${lang}_XCODE_ARCHS}" PARENT_SCOPE)
   set(CMAKE_${lang}_CL_SHOWINCLUDES_PREFIX "${CMAKE_${lang}_CL_SHOWINCLUDES_PREFIX}" PARENT_SCOPE)
   set(CMAKE_${lang}_COMPILER_VERSION "${CMAKE_${lang}_COMPILER_VERSION}" PARENT_SCOPE)
   set(CMAKE_${lang}_COMPILER_VERSION_INTERNAL "${CMAKE_${lang}_COMPILER_VERSION_INTERNAL}" PARENT_SCOPE)
@@ -380,8 +380,10 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
         endif()
       endif()
     endif()
-    if("${CMAKE_${lang}_COMPILER_ID_OUTPUT}" MATCHES "CURRENT_ARCH=([^%\r\n]+)[\r\n]")
-      set(CMAKE_${lang}_XCODE_CURRENT_ARCH "${CMAKE_MATCH_1}" PARENT_SCOPE)
+    if("${CMAKE_${lang}_COMPILER_ID_OUTPUT}" MATCHES "ARCHS=([^%\r\n]+)[\r\n]")
+      set(CMAKE_${lang}_XCODE_ARCHS "${CMAKE_MATCH_1}")
+      separate_arguments(CMAKE_${lang}_XCODE_ARCHS)
+      set(CMAKE_${lang}_XCODE_ARCHS "${CMAKE_${lang}_XCODE_ARCHS}" PARENT_SCOPE)
     endif()
   else()
     execute_process(

Modules/CompilerId/Xcode-3.pbxproj.in

@@ -58,7 +58,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "echo \"GCC_VERSION=$GCC_VERSION\" ; echo \"CURRENT_ARCH=$CURRENT_ARCH\"";
+			shellScript = "echo \"GCC_VERSION=$GCC_VERSION\" ; echo \"ARCHS=$ARCHS\"";
 			showEnvVarsInLog = 0;
 		};
 		2C18F0B515DC1DCE00593670 = {

Source/cmGlobalXCodeGenerator.cxx

@@ -3156,8 +3156,13 @@ void cmGlobalXCodeGenerator::ComputeArchitectures(cmMakefile* mf)
   if (this->Architectures.empty()) {
     // With no ARCHS we use ONLY_ACTIVE_ARCH.
     // Look up the arch that Xcode chooses in this case.
-    if (const char* arch = mf->GetDefinition("CMAKE_XCODE_CURRENT_ARCH")) {
+    if (const char* arch = mf->GetDefinition("CMAKE_XCODE_ARCHS")) {
       this->ObjectDirArchDefault = arch;
+      // We expect only one arch but choose the first just in case.
+      std::string::size_type pos = this->ObjectDirArchDefault.find(';');
+      if (pos != std::string::npos) {
+        this->ObjectDirArchDefault = this->ObjectDirArchDefault.substr(0, pos);
+      }
     }
   }