cmd/go: fix cgo test when min macOS version is set

Regression tests for #24161 use a macro to conditionally compile some
stub definitions. The macro tests that the minimum macOS version is
less than 10.12.

We get duplicate definitions when building this test with
CGO_CFLAGS=-mmacosx-version-min=10.x where 10.x < 10.12. With this
change, we use a different macro, __MAC_OS_X_VERSION_MAX_ALLOWED__,
which tests the SDK version instead of the minimum macOS version. This
checks whether these definitions are present in headers.

After this change, 'go tool dist test cgo_test' should pass with
CGO_FLAGS=-mmacosx-version-min=10.10.

Updates #35459

Change-Id: I88d63601c94b0369c73c38d216a2d41ba7d4e579
Reviewed-on: https://go-review.googlesource.com/c/go/+/216243
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Author: Jay Conrod

misc/cgo/test/testdata/issue24161e0/main.go

@@ -12,7 +12,7 @@ package issue24161e0
 #include <TargetConditionals.h>
 #include <CoreFoundation/CoreFoundation.h>
 #include <Security/Security.h>
-#if TARGET_OS_IPHONE == 0 && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200
+#if TARGET_OS_IPHONE == 0 && __MAC_OS_X_VERSION_MAX_ALLOWED < 101200
   typedef CFStringRef SecKeyAlgorithm;
   static CFDataRef SecKeyCreateSignature(SecKeyRef key, SecKeyAlgorithm algorithm, CFDataRef dataToSign, CFErrorRef *error){return NULL;}
   #define kSecKeyAlgorithmECDSASignatureDigestX962SHA1 foo()

misc/cgo/test/testdata/issue24161e1/main.go

@@ -12,7 +12,7 @@ package issue24161e1
 #include <TargetConditionals.h>
 #include <CoreFoundation/CoreFoundation.h>
 #include <Security/Security.h>
-#if TARGET_OS_IPHONE == 0 && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200
+#if TARGET_OS_IPHONE == 0 && __MAC_OS_X_VERSION_MAX_ALLOWED < 101200
   typedef CFStringRef SecKeyAlgorithm;
   static CFDataRef SecKeyCreateSignature(SecKeyRef key, SecKeyAlgorithm algorithm, CFDataRef dataToSign, CFErrorRef *error){return NULL;}
   #define kSecKeyAlgorithmECDSASignatureDigestX962SHA1 foo()

misc/cgo/test/testdata/issue24161e2/main.go

@@ -12,7 +12,7 @@ package issue24161e2
 #include <TargetConditionals.h>
 #include <CoreFoundation/CoreFoundation.h>
 #include <Security/Security.h>
-#if TARGET_OS_IPHONE == 0 && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200
+#if TARGET_OS_IPHONE == 0 && __MAC_OS_X_VERSION_MAX_ALLOWED < 101200
   typedef CFStringRef SecKeyAlgorithm;
   static CFDataRef SecKeyCreateSignature(SecKeyRef key, SecKeyAlgorithm algorithm, CFDataRef dataToSign, CFErrorRef *error){return NULL;}
   #define kSecKeyAlgorithmECDSASignatureDigestX962SHA1 foo()