fix issues

Author: GrigoryPervakov

cmake/darwin/default_libs.cmake

@@ -15,5 +15,18 @@ set(CMAKE_OSX_DEPLOYMENT_TARGET 10.15)
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 
+if(NOT CMAKE_CROSSCOMPILING)
+    execute_process(
+        COMMAND xcrun --sdk macosx --show-sdk-version
+        OUTPUT_VARIABLE OS_DARWIN_SDK_VERSION
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(${OS_DARWIN_SDK_VERSION} MATCHES "^[0-9]+\\.[0-9]+")
+        message(STATUS "Detected OSX SDK Version: ${OS_DARWIN_SDK_VERSION}")
+    else ()
+        message(WARNING "Unexpected OSX SDK Version: ${OS_DARWIN_SDK_VERSION}")
+    endif()
+endif()
+
 include (cmake/unwind.cmake)
-include (cmake/cxx.cmake)
+include (cmake/cxx.cmake)

contrib/postgres-cmake/CMakeLists.txt

@@ -80,22 +80,10 @@ if (OS_DARWIN OR OS_FREEBSD OR USE_MUSL)
 endif()
 
 # Mac 15.4 / Xcode 16.3 started defining srtchrnul
-# Could be cleaned up after resolved in upstream https://www.postgresql.org/message-id/flat/385134.1743523038%40sss.pgh.pa.us
-if (OS_DARWIN AND NOT USE_MUSL)
-    execute_process(
-            COMMAND xcrun --sdk macosx --show-sdk-version
-            OUTPUT_VARIABLE XCRUN
-            OUTPUT_STRIP_TRAILING_WHITESPACE
-    )
-
-    string(REGEX MATCH "([0-9]+)\\.([0-9]+)" _ ${XCRUN})
-    set(SDK_VERSION_MAJOR "${CMAKE_MATCH_1}")
-    set(SDK_VERSION_MINOR "${CMAKE_MATCH_2}")
-
-    message(STATUS "Detected SDK Version: ${SDK_VERSION_MAJOR}.${SDK_VERSION_MINOR}")
-    if(SDK_VERSION_MAJOR GREATER 15 OR (SDK_VERSION_MAJOR EQUAL 15 AND SDK_VERSION_MINOR GREATER_EQUAL 4))
-        target_compile_definitions(_libpq PRIVATE -DHAVE_STRCHRNUL)
-    endif()
+# Could be cleaned up if properly resolved in upstream
+# https://www.postgresql.org/message-id/flat/385134.1743523038%40sss.pgh.pa.us
+if (OS_DARWIN AND OS_DARWIN_SDK_VERSION AND OS_DARWIN_SDK_VERSION VERSION_GREATER_EQUAL 15.4)
+    target_compile_definitions(_libpq PRIVATE -DHAVE_STRCHRNUL)
 endif()
 
 target_link_libraries (_libpq PRIVATE OpenSSL::SSL)