diff --git a/src/client/linux/dump_writer_common/thread_info.h b/src/client/linux/dump_writer_common/thread_info.h
index 2a99bb97..5f24fd6b 100644
--- a/src/client/linux/dump_writer_common/thread_info.h
+++ b/src/client/linux/dump_writer_common/thread_info.h
@@ -31,22 +31,7 @@
 #define CLIENT_LINUX_DUMP_WRITER_COMMON_THREAD_INFO_H_
 
 #include <sys/ucontext.h>
-
-// TODO(primiano): remove this after Chromium has stably rolled to NDK r10d.
-// Historical context: NDK releases < r10d had a typo in sys/user.h (mxcsr_mask
-// instead of mxcr_mask), which is fixed in r10d. However, just switching to use
-// the correct one (mxcr_mask) would put Breakpad in a state where it can be
-// rolled in chromium only atomically with the r10d NDK. A revert of either
-// project (android_tools, breakpad) would make the other one unrollable.
-// This hack makes breakpad code compatible with both r10c and r10d NDKs,
-// reducing the dependency entangling with android_tools.
-#if defined (__ANDROID__)
-#define mxcsr_mask mxcr_mask
 #include <sys/user.h>
-#undef mxcsr_mask
-#else
-#include <sys/user.h>
-#endif
 
 #include "client/linux/dump_writer_common/raw_context_cpu.h"
 #include "common/memory.h"
diff --git a/src/common/android/include/sys/user.h b/src/common/android/include/sys/user.h
index d41a82cb..05b22ced 100644
--- a/src/common/android/include/sys/user.h
+++ b/src/common/android/include/sys/user.h
@@ -34,9 +34,11 @@
 // glibc) and therefore avoid doing otherwise awkward #ifdefs in the code.
 // The following quirks are currently handled by this file:
 // - MIPS: Keep using forked definitions of user.h structs. The definition in
-//   the NDK is completely different.
-//   Internal bug b/18097715
+//     the NDK is completely different. Internal bug b/18097715
 // - i386: Use the Android NDK but alias user_fxsr_struct > user_fpxregs_struct.
+// - x86_64: Override a typo in user_fpregs_struct (mxcsr_mask -> mxcr_mask).
+//     The typo has been fixed in NDK r10d, but a preprocessor workaround is
+//     required to make breakpad build with r10c and lower (more details below).
 // - Other platforms: Just use the Android NDK unchanged.
 
 #ifdef __mips__
@@ -113,8 +115,24 @@ struct user_fpregs_struct {
 
 #else  //  __mips__
 
+// TODO(primiano): remove this after Chromium has stably rolled to NDK r10d.
+// Historical context: NDK releases < r10d had a typo in sys/user.h (mxcsr_mask
+// instead of mxcr_mask), which is fixed in r10d. However, just switching to use
+// the correct one (mxcr_mask) would put Breakpad in a state where it can be
+// rolled in chromium only atomically with the r10d NDK. A revert of either
+// project (android_tools, breakpad) would make the other one unrollable.
+// This hack makes breakpad code compatible with both r10c and r10d NDKs,
+// reducing the dependency entangling with android_tools.
+#if defined(__x86_64__)
+#define mxcsr_mask mxcr_mask
+#endif
+
 #include_next <sys/user.h>
 
+#if defined(__x86_64__)
+#undef mxcsr_mask
+#endif
+
 #ifdef __i386__
 #ifdef __cplusplus
 extern "C" {