Fix check for macOS 10.10.

The constant is 101000, not 10100, but fortunately, this worked anyway
since 10.9's constant is 1090, and nothing else was defined in between.

Author: QuLogic

src/_macosx.m

@@ -15,7 +15,7 @@
 #if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
 #define COMPILING_FOR_10_7
 #endif
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 10100
+#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101000
 #define COMPILING_FOR_10_10
 #endif