Fixes on linker executable variables per target.

* `prefix` should be `sdk` in runtime cmake list file
* typo on variable existence checking

Author: gonzalolarralde

cmake/modules/SwiftConfigureSDK.cmake

@@ -23,7 +23,7 @@ function(_report_sdk prefix)
   message(STATUS "  Architectures: ${SWIFT_SDK_${prefix}_ARCHITECTURES}")
   message(STATUS "  Object Format: ${SWIFT_SDK_${prefix}_OBJECT_FORMAT}")
   foreach(arch ${SWIFT_SDK_${prefix}_ARCHITECTURES})
-    if(${SWIFT_SDK_${prefix}_ARCH_${arch}_LINKER})
+    if(SWIFT_SDK_${prefix}_ARCH_${arch}_LINKER)
       message(STATUS "  Linker (${arch}): ${SWIFT_SDK_${prefix}_ARCH_${arch}_LINKER}")
     else()
       message(STATUS "  Linker (${arch}): ${CMAKE_LINKER}")

stdlib/public/runtime/CMakeLists.txt

@@ -165,8 +165,8 @@ foreach(sdk ${ELFISH_SDKS})
     set(section_magic_end_obj "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/section_magic_end-${arch_suffix}.dir/swift_sections.S${CMAKE_C_OUTPUT_EXTENSION}")
 
     set(ld_EXECUTABLE ${CMAKE_LINKER})
-    if(${SWIFT_SDK_${prefix}_ARCH_${arch}_LINKER})
-      set(ld_EXECUTABLE ${SWIFT_SDK_${prefix}_ARCH_${arch}_LINKER})
+    if(SWIFT_SDK_${sdk}_ARCH_${arch}_LINKER)
+      set(ld_EXECUTABLE ${SWIFT_SDK_${sdk}_ARCH_${arch}_LINKER})
     endif()
 
     add_custom_command_target(section_magic_${arch_suffix}_begin_object