(conan-io#16812) libmysqlclient: move check_min_cppstd to validate_build

* libmysqlclient: move check_min_cppstd to validate build

* libmysqlclient: move some logic back to validate()

* formatting

recipes/libmysqlclient/all/conanfile.py

@@ -69,10 +69,14 @@ def requirements(self):
         if self.settings.os == "FreeBSD":
             self.requires("libunwind/1.6.2")
 
-    def validate(self):
+    def validate_build(self):
         if self.settings.compiler.get_safe("cppstd"):
             check_min_cppstd(self, self._min_cppstd)
 
+        if hasattr(self, "settings_build") and cross_building(self, skip_x64_x86=True):
+            raise ConanInvalidConfiguration("Cross compilation not yet supported by the recipe. Contributions are welcomed.")
+
+    def validate(self):
         def loose_lt_semver(v1, v2):
             lv1 = [int(v) for v in v1.split(".")]
             lv2 = [int(v) for v in v2.split(".")]
@@ -83,9 +87,6 @@ def loose_lt_semver(v1, v2):
         if minimum_version and loose_lt_semver(str(self.settings.compiler.version), minimum_version):
             raise ConanInvalidConfiguration(f"{self.ref} requires {self.settings.compiler} {minimum_version} or newer")
 
-        if hasattr(self, "settings_build") and cross_building(self, skip_x64_x86=True):
-            raise ConanInvalidConfiguration("Cross compilation not yet supported by the recipe. Contributions are welcomed.")
-
         # Sice 8.0.17 this doesn't support shared library on MacOS.
         # https://github.com/mysql/mysql-server/blob/mysql-8.0.17/cmake/libutils.cmake#L333-L335
         if self.settings.compiler == "apple-clang" and self.options.shared: