[sanitizer] Use the correct macro to check glibc version.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@185324 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/sanitizer_common/sanitizer_linux_libcdep.cc b/lib/sanitizer_common/sanitizer_linux_libcdep.cc
index fe8e67d..239df35 100644
--- a/lib/sanitizer_common/sanitizer_linux_libcdep.cc
+++ b/lib/sanitizer_common/sanitizer_linux_libcdep.cc
@@ -197,7 +197,7 @@
 // sizeof(struct thread) from glibc.
 // There has been a report of this being different on glibc 2.11. We don't know
 // when this change happened, so 2.12 is a conservative estimate.
-#if __GNUC_PREREQ(2, 12)
+#if __GLIBC_PREREQ(2, 12)
 const uptr kThreadDescriptorSize = FIRST_32_SECOND_64(1216, 2304);
 #else
 const uptr kThreadDescriptorSize = FIRST_32_SECOND_64(1168, 2304);