MinGW: Use __mingw_strtold instead of strtold.

The latter fails to parse hex floating point literals.

dmd2/expression.c

@@ -2620,6 +2620,8 @@ void floatToBuffer(OutBuffer *buf, Type *type, real_t value)
     __locale_decpoint = ".";
     real_t r = strtold(buffer, NULL);
     __locale_decpoint = save;
+#elif IN_LLVM
+    real_t r = Port::strtold(buffer, NULL);
 #else
     real_t r = strtold(buffer, NULL);
 #endif

dmd2/lexer.c

@@ -2364,6 +2364,8 @@ done:
 #endif
 #ifdef IN_GCC
     t->float80value = real_t::parse((char *)stringbuffer.data, real_t::LongDouble);
+#elif IN_LLVM
+    t->float80value = Port::strtold((char *)stringbuffer.data, NULL);
 #else
     t->float80value = strtold((char *)stringbuffer.data, NULL);
 #endif

dmd2/root/port.c

@@ -670,3 +670,18 @@ char *Port::strupr(char *s)
 }
 
 #endif
+
+
+#if IN_LLVM
+#if __MINGW32__
+longdouble Port::strtold(const char *str, char **pend)
+{
+    return __mingw_strtold(str, pend);
+}
+#else
+longdouble Port::strtold(const char *str, char **pend)
+{
+    return ::strtold(str, pend);
+}
+#endif
+#endif

dmd2/root/port.h

@@ -61,6 +61,9 @@ struct Port
     static longdouble fmodl(longdouble x, longdouble y);
 
     static ulonglong strtoull(const char *p, char **pend, int base);
+#if IN_LLVM
+    static longdouble strtold(const char *str, char **pend);
+#endif
 
     static char *ull_to_string(char *buffer, ulonglong ull);
     static wchar_t *ull_to_string(wchar_t *buffer, ulonglong ull);