Revert "Ogg symbols should be private by default"

This reverts commit d7d6e29.

If the symbols are private, then they aren't available in the framework when linking opus

Xcode/ogg/ogg.xcodeproj/project.pbxproj

@@ -264,7 +264,6 @@
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
-				GCC_SYMBOLS_PRIVATE_EXTERN = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
@@ -324,7 +323,6 @@
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_NO_COMMON_BLOCKS = YES;
-				GCC_SYMBOLS_PRIVATE_EXTERN = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;