use fpclassify() etc replacements in FreeBSD + clang to avoid a FreeBSD math.h header bug

src/duk_features.h

@@ -152,6 +152,11 @@ static __inline__ unsigned long long duk_rdtsc(void) {
 #define  DUK_F_AMIGAOS
 #endif
 
+/* FreeBSD. */
+#if defined(__FreeBSD__)
+#define  DUK_F_FREEBSD
+#endif
+
 /* GCC and GCC version convenience define. */
 #if defined(__GNUC__)
 #define  DUK_F_GCC
@@ -163,6 +168,11 @@ static __inline__ unsigned long long duk_rdtsc(void) {
 #endif
 #endif
 
+/* Clang. */
+#if defined(__clang__)
+#define  DUK_F_CLANG
+#endif
+
 /*
  *  Platform detection and system includes
  *
@@ -777,9 +787,24 @@ extern double duk_computed_nan;
 #undef  DUK_USE_REPL_SIGNBIT
 #undef  DUK_USE_REPL_ISFINITE
 #undef  DUK_USE_REPL_ISNAN
+
+/* complex condition broken into separate parts */
+#undef  DUK_F_USE_REPL_ALL
 #if !(defined(FP_NAN) && defined(FP_INFINITE) && defined(FP_ZERO) && \
-      defined(FP_SUBNORMAL) && defined(FP_NORMAL)) || \
-    (defined(DUK_F_AMIGAOS) && defined(__VBCC__))
+      defined(FP_SUBNORMAL) && defined(FP_NORMAL))
+/* missing some obvious constants */
+#define  DUK_F_USE_REPL_ALL
+#elif defined(DUK_F_AMIGAOS) && defined(__VBCC__)
+/* VBCC is missing the built-ins even in C99 mode (perhaps a header issue) */
+#define  DUK_F_USE_REPL_ALL
+#elif defined(DUK_F_FREEBSD) && defined(DUK_F_CLANG)
+/* Placeholder fix for (detection is wider than necessary):
+ * http://llvm.org/bugs/show_bug.cgi?id=17788
+ */
+#define  DUK_F_USE_REPL_ALL
+#endif
+
+#if defined(DUK_F_USE_REPL_ALL)
 #define  DUK_USE_REPL_FPCLASSIFY
 #define  DUK_USE_REPL_SIGNBIT
 #define  DUK_USE_REPL_ISFINITE
@@ -805,6 +830,10 @@ extern double duk_computed_nan;
 #define  DUK_FP_NORMAL        FP_NORMAL
 #endif
 
+#if defined(DUK_F_USE_REPL_ALL)
+#undef  DUK_F_USE_REPL_ALL
+#endif
+
 /* Some math functions are C99 only.  This is also an issue with some
  * embedded environments using uclibc where uclibc has been configured
  * not to provide some functions.  For now, use replacements whenever