Don't run cargo-hack for iOS

cargo-hack tries to run some rustc command that needs the
iphonesimulator SDK for iOS.  Just skip it.

Author: asomers

.cirrus.yml

@@ -20,8 +20,8 @@ build: &BUILD
     - $TOOL +$TOOLCHAIN $BUILD $ZFLAGS --target $TARGET --all-targets
     - $TOOL +$TOOLCHAIN doc $ZFLAGS --no-deps --target $TARGET
     - $TOOL +$TOOLCHAIN clippy $ZFLAGS --target $TARGET -- $CLIPPYFLAGS
-    - $TOOL install cargo-hack
-    - $TOOL hack check --target $TARGET --each-feature
+    - [ -n "$NOHACK" ] || $TOOL install cargo-hack
+    - [ -n "$NOHACK" ] || $TOOL hack check --target $TARGET --each-feature
 
 # Tests that do require executing the binaries
 test: &TEST
@@ -196,13 +196,17 @@ task:
     # https://github.com/rust-embedded/cross/issues/535
     - name: iOS aarch64
       env:
+        # cargo hack tries to invoke the iphonesimulator SDK for iOS
+        NOHACK: 1
         TARGET: aarch64-apple-ios
         # Rustup only supports cross-building from arbitrary hosts for iOS at
         # 1.49.0 and above.  Below that it's possible to cross-build from an OSX
         # host, but OSX VMs are more expensive than Linux VMs.
         TOOLCHAIN: 1.49.0
     - name: iOS x86_64
       env:
+        # cargo hack tries to invoke the iphonesimulator SDK for iOS
+        NOHACK: 1
         TARGET: x86_64-apple-ios
         TOOLCHAIN: 1.49.0
     # Cross testing on powerpc fails with "undefined reference to renameat2".