feat(xcode): --cross-compiling overrides arch-specific settings

pylib/gyp/xcode_emulation.py

@@ -654,28 +654,32 @@ def GetCflags(self, configname, arch=None):
         self._WarnUnimplemented("MACH_O_TYPE")
         self._WarnUnimplemented("PRODUCT_TYPE")
 
-        if arch is not None:
-            archs = [arch]
-        else:
-            assert self.configname
-            archs = self.GetActiveArchs(self.configname)
-        if len(archs) != 1:
-            # TODO: Supporting fat binaries will be annoying.
-            self._WarnUnimplemented("ARCHS")
-            archs = ["i386"]
-        cflags.append("-arch " + archs[0])
-
-        if archs[0] in ("i386", "x86_64"):
-            if self._Test("GCC_ENABLE_SSE3_EXTENSIONS", "YES", default="NO"):
-                cflags.append("-msse3")
-            if self._Test(
-                "GCC_ENABLE_SUPPLEMENTAL_SSE3_INSTRUCTIONS", "YES", default="NO"
-            ):
-                cflags.append("-mssse3")  # Note 3rd 's'.
-            if self._Test("GCC_ENABLE_SSE41_EXTENSIONS", "YES", default="NO"):
-                cflags.append("-msse4.1")
-            if self._Test("GCC_ENABLE_SSE42_EXTENSIONS", "YES", default="NO"):
-                cflags.append("-msse4.2")
+        # If GYP_CROSSCOMPILE (--cross-compiling), disable architecture-specific
+        # additions and assume these will be provided as required via CC_host,
+        # CXX_host, CC_target and CXX_target.
+        if not gyp.common.CrossCompileRequested():
+            if arch is not None:
+                archs = [arch]
+            else:
+                assert self.configname
+                archs = self.GetActiveArchs(self.configname)
+            if len(archs) != 1:
+                # TODO: Supporting fat binaries will be annoying.
+                self._WarnUnimplemented("ARCHS")
+                archs = ["i386"]
+            cflags.append("-arch " + archs[0])
+
+            if archs[0] in ("i386", "x86_64"):
+                if self._Test("GCC_ENABLE_SSE3_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse3")
+                if self._Test(
+                    "GCC_ENABLE_SUPPLEMENTAL_SSE3_INSTRUCTIONS", "YES", default="NO"
+                ):
+                    cflags.append("-mssse3")  # Note 3rd 's'.
+                if self._Test("GCC_ENABLE_SSE41_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse4.1")
+                if self._Test("GCC_ENABLE_SSE42_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse4.2")
 
         cflags += self._Settings().get("WARNING_CFLAGS", [])
 
@@ -938,16 +942,17 @@ def GetLdflags(self, configname, product_dir, gyp_to_build_path, arch=None):
                 + gyp_to_build_path(self._Settings()["ORDER_FILE"])
             )
 
-        if arch is not None:
-            archs = [arch]
-        else:
-            assert self.configname
-            archs = self.GetActiveArchs(self.configname)
-        if len(archs) != 1:
-            # TODO: Supporting fat binaries will be annoying.
-            self._WarnUnimplemented("ARCHS")
-            archs = ["i386"]
-        ldflags.append("-arch " + archs[0])
+        if not gyp.common.CrossCompileRequested():
+            if arch is not None:
+                archs = [arch]
+            else:
+                assert self.configname
+                archs = self.GetActiveArchs(self.configname)
+            if len(archs) != 1:
+                # TODO: Supporting fat binaries will be annoying.
+                self._WarnUnimplemented("ARCHS")
+                archs = ["i386"]
+            ldflags.append("-arch " + archs[0])
 
         # Xcode adds the product directory by default.
         # Rewrite -L. to -L./ to work around http://www.openradar.me/25313838