add global macros for easily toggling warning flags

in some cases, eg., -Wformat-nonliteral, warnings may be generated for
valid uses of C, but the warning is still useful. this allows certain warnings
to be disabled as necessary

src/bin/e.h

@@ -376,4 +376,32 @@ extern EINTERN double e_first_frame_start_time;
 # define DELD(obj, num)
 #endif
 
+/* for disabling compiler warnings
+ * http://stackoverflow.com/questions/3378560/how-to-disable-gcc-warnings-for-a-few-lines-of-code
+ */
+#define DIAG_STR(s) #s
+#define DIAG_JOINSTR(x,y) DIAG_STR(x ## y)
+#ifdef _MSC_VER
+#define DIAG_DO_PRAGMA(x) __pragma (#x)
+#define DIAG_PRAGMA(compiler,x) DIAG_DO_PRAGMA(warning(x))
+#else
+#define DIAG_DO_PRAGMA(x) _Pragma (#x)
+#define DIAG_PRAGMA(compiler,x) DIAG_DO_PRAGMA(compiler diagnostic x)
+#endif
+#if defined(__clang__)
+# define DISABLE_WARNING(gcc_unused,clang_option,msvc_unused) DIAG_PRAGMA(clang,push) DIAG_PRAGMA(clang,ignored DIAG_JOINSTR(-W,clang_option))
+# define ENABLE_WARNING(gcc_unused,clang_option,msvc_unused) DIAG_PRAGMA(clang,pop)
+#elif defined(_MSC_VER)
+# define DISABLE_WARNING(gcc_unused,clang_unused,msvc_errorcode) DIAG_PRAGMA(msvc,push) DIAG_DO_PRAGMA(warning(disable:##msvc_errorcode))
+# define ENABLE_WARNING(gcc_unused,clang_unused,msvc_errorcode) DIAG_PRAGMA(msvc,pop)
+#elif defined(__GNUC__)
+#if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406
+# define DISABLE_WARNING(gcc_option,clang_unused,msvc_unused) DIAG_PRAGMA(GCC,push) DIAG_PRAGMA(GCC,ignored DIAG_JOINSTR(-W,gcc_option))
+# define ENABLE_WARNING(gcc_option,clang_unused,msvc_unused) DIAG_PRAGMA(GCC,pop)
+#else
+# define DISABLE_WARNING(gcc_option,clang_unused,msvc_unused) DIAG_PRAGMA(GCC,ignored DIAG_JOINSTR(-W,gcc_option))
+# define ENABLE_WARNING(gcc_option,clang_option,msvc_unused) DIAG_PRAGMA(GCC,warning DIAG_JOINSTR(-W,gcc_option))
+#endif
+#endif
+
 #endif