mac: fix sdk version comparison

Change-Id: Iccd1c76b691c734b9049a8c9a14d9b01fe0b665c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864374Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707105}

base/mac/foundation_util.h

@@ -53,7 +53,9 @@ typedef CR_FORWARD_ENUM(unsigned int, NSSearchPathDirectory);
 typedef unsigned int NSSearchPathDomainMask;
 #endif
 
-#if defined(OS_IOS) || defined(MAC_OS_X_VERSION_10_15)
+#if defined(OS_IOS) ||                  \
+    (defined(MAC_OS_X_VERSION_10_15) && \
+     MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15)
 typedef struct CF_BRIDGED_TYPE(id) __SecCertificate* SecCertificateRef;
 typedef struct CF_BRIDGED_TYPE(id) __SecKey* SecKeyRef;
 typedef struct CF_BRIDGED_TYPE(id) __SecPolicy* SecPolicyRef;