libc fortify: make fcntl.h use diagnose_if

Bug: 12231437
Test: m checkbuild on bionic internal master; CtsBionicTestCases show
no new failures.

Change-Id: I4a31d9e65ed5820a581261a7e8f63a83e44936c3
diff --git a/tests/fortify_compilation_test.cpp b/tests/fortify_compilation_test.cpp
index bb2b770..771915c 100644
--- a/tests/fortify_compilation_test.cpp
+++ b/tests/fortify_compilation_test.cpp
@@ -206,7 +206,7 @@
 void test_open() {
   // NOLINTNEXTLINE(whitespace/line_length)
   // GCC: error: call to '__creat_missing_mode' declared with attribute error: called with O_CREAT, but missing mode
-  // CLANG: error: call to unavailable function 'open': called with O_CREAT, but missing mode
+  // CLANG: error: 'open' called with O_CREAT, but missing mode
   open("/dev/null", O_CREAT);
 
   // NOLINTNEXTLINE(whitespace/line_length)