Fix typo in macro: FOLLY_HAVE_SDT

Summary:
`FOLLY_HAS_STD` and `FOLLY_HAVE_STD` are now `FOLLY_HAVE_SDT`.

This typo reveals that the tests aren't run on platforms that don't have this feature enabled :/

Reviewed By: yfeldblum

Differential Revision: D30780817

fbshipit-source-id: 338fdd5e5b08f3b5347609dd783f0a75506f9e30

folly/tracing/StaticTracepoint.h

@@ -21,7 +21,7 @@
 #if FOLLY_HAVE_ELF && (defined(__x86_64__) || defined(__i386__)) && \
     !FOLLY_DISABLE_SDT
 
-#define FOLLY_HAS_STD 1
+#define FOLLY_HAVE_SDT 1
 
 #include <folly/tracing/StaticTracepoint-ELFx86.h>
 
@@ -38,7 +38,7 @@
 
 #else
 
-#define FOLLY_HAVE_STD 0
+#define FOLLY_HAVE_SDT 0
 
 #define FOLLY_SDT(provider, name, ...) \
   do {                                 \

folly/tracing/test/StaticTracepointTest.cpp

@@ -35,7 +35,7 @@
 #include <folly/portability/Unistd.h>
 #include <folly/tracing/test/StaticTracepointTestModule.h>
 
-#if FOLLY_HAS_STD
+#if FOLLY_HAVE_SDT
 
 static const std::string kUSDTSubsectionName = FOLLY_SDT_NOTE_NAME;
 static const int kUSDTNoteType = FOLLY_SDT_NOTE_TYPE;