Visual Studio 2013 support + strtof + inline

- VC12 has better C99 library support due to C++11
- defined strtof for VC11 or older
- define "inline" only if the C compiler is used

include/mruby/value.h

@@ -51,25 +51,29 @@
 typedef short mrb_sym;
 
 #ifdef _MSC_VER
-# define _ALLOW_KEYWORD_MACROS
-# include <float.h>
-# define inline __inline
+# ifndef __cplusplus
+#  define inline __inline
+# endif
 # define snprintf _snprintf
-# define isnan _isnan
-# define isinf(n) (!_finite(n) && !_isnan(n))
-# define strtoll _strtoi64
-# define PRId32 "I32d"
-# define PRIi32 "I32i"
-# define PRIo32 "I32o"
-# define PRIx32 "I32x"
-# define PRIX32 "I32X"
-# define PRId64 "I64d"
-# define PRIi64 "I64i"
-# define PRIo64 "I64o"
-# define PRIx64 "I64x"
-# define PRIX64 "I64X"
-#else
-# include <inttypes.h>
+# if _MSC_VER < 1800
+#  include <float.h>
+#  define isnan _isnan
+#  define isinf(n) (!_finite(n) && !_isnan(n))
+#  define strtoll _strtoi64
+#  define strtof (float)strtod
+#  define PRId32 "I32d"
+#  define PRIi32 "I32i"
+#  define PRIo32 "I32o"
+#  define PRIx32 "I32x"
+#  define PRIX32 "I32X"
+#  define PRId64 "I64d"
+#  define PRIi64 "I64i"
+#  define PRIo64 "I64o"
+#  define PRIx64 "I64x"
+#  define PRIX64 "I64X"
+# else
+#  include <inttypes.h>
+# endif
 #endif
 
 typedef uint8_t mrb_bool;

mrbgems/mruby-math/src/math.c

@@ -12,8 +12,8 @@
 #define domain_error(msg) \
     mrb_raise(mrb, E_RANGE_ERROR, "Numerical argument is out of domain - " #msg)
 
-/* math functions not provided under Microsoft Visual C++ */
-#ifdef _MSC_VER
+/* math functions not provided by Microsoft Visual C++ 2012 or older */
+#if defined _MSC_VER && _MSC_VER < 1800
 
 #define MATH_TOLERANCE 1E-12
 
@@ -87,6 +87,12 @@ erfc(double x)
   return one_sqrtpi*exp(-x*x)*q2;
 }
 
+double
+log2(double x)
+{
+    return log10(x)/log10(2.0);
+}
+
 #endif
 
 /*
@@ -358,18 +364,6 @@ math_atanh(mrb_state *mrb, mrb_value obj)
 # define log10(x) ((x) < 0.0 ? nan("") : log10(x))
 #endif
 
-#ifndef log2
-#ifndef HAVE_LOG2
-double
-log2(double x)
-{
-    return log10(x)/log10(2.0);
-}
-#else
-extern double log2(double);
-#endif
-#endif
-
 /*
  *  call-seq:
  *     Math.exp(x)    -> float

mrbgems/mruby-sprintf/src/sprintf.c

@@ -15,10 +15,6 @@
 #include <math.h>
 #include <ctype.h>
 
-#ifdef _MSC_VER
-#include <float.h>
-#endif
-
 #ifdef HAVE_IEEEFP_H
 #include <ieeefp.h>
 #endif