Disable RandTest.Fork on iOS.

iOS doesn't support fork.

Bug: chromium:890115
Change-Id: Idac6c0e180bbc1088ca5c562b8c1e646bff00b25
Reviewed-on: https://boringssl-review.googlesource.com/32164
Reviewed-by: Steven Valdez <svaldez@google.com>

crypto/rand_extra/rand_test.cc

diff --git a/crypto/rand_extra/rand_test.cc b/crypto/rand_extra/rand_test.cc
index 183c4f7..d0a7e40 100644
--- a/crypto/rand_extra/rand_test.cc
+++ b/crypto/rand_extra/rand_test.cc
@@ -50,7 +50,8 @@
   EXPECT_NE(Bytes(buf2), Bytes(kZeros));
 }
 
-#if !defined(OPENSSL_WINDOWS) && !defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
+#if !defined(OPENSSL_WINDOWS) && !defined(OPENSSL_IOS) && \
+    !defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
 static bool ForkAndRand(bssl::Span<uint8_t> out) {
   int pipefds[2];
   if (pipe(pipefds) < 0) {
@@ -144,7 +145,8 @@
   EXPECT_NE(Bytes(buf2), Bytes(kZeros));
   EXPECT_NE(Bytes(buf3), Bytes(kZeros));
 }
-#endif  // !OPENSSL_WINDOWS && !BORINGSSL_UNSAFE_DETERMINISTIC_MODE
+#endif  // !OPENSSL_WINDOWS && !OPENSSL_IOS &&
+        // !BORINGSSL_UNSAFE_DETERMINISTIC_MODE
 
 #if defined(OPENSSL_THREADS)
 static void RunConcurrentRands(size_t num_threads) {

include/openssl/base.h

diff --git a/include/openssl/base.h b/include/openssl/base.h
index e287de7..c0d7a8c 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -120,6 +120,9 @@
 
 #if defined(__APPLE__)
 #define OPENSSL_APPLE
+#if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
+#define OPENSSL_IOS
+#endif
 #endif
 
 #if defined(_WIN32)