I encountered a few bugs (compilation and others) in the newlib-4.3.0.20230120 release. Compiling using GCC version 12.2.0 for FreeRTOS and an in-house processor. 1. The function declaration for mcwidth in newlib/libc/string/wcwidth.c does not match the prototype in newlib/libc/include/wchar.h . 1. Should be including sys/types.h not sys/_types.h in newlib/libc/include/stdio.h 1. In order to build boost and some other third party libraries, need to have the following defined in newlib/libc/include/glob.h #define GLOB_NOMATCH (-3) /* No matches found. */ #define GLOB_NOSYS (-4) /* Not implemented. */ /* Previous versions of this file defined GLOB_ABEND instead of * GLOB_ABORTED. Provide a compatibility definition here. */ #define GLOB_ABORTED GLOB_ABEND 1. In newlib/libc/locale/locale.c need to add int ret = 0; inside the first #else clause in function __loadlocale . This is after the #ifdef __CYGWIN__ line. 1. The return type for pthread_yield should be int not void in newlib/libc/include/pthread.h. This matches both Linux and FreeRTOSLabs posix threads. Arcfield Proprietary E-MAIL CONTENT CLASSIFICATION NOTICE CONFIDENTIAL AND/OR PROPRIETARY INFORMATION OF ARCFIELD. This e-mail message and/or its attachment contains confidential and/or proprietary information of Arcfield that may only be received, disclosed, or used as authorized by Arcfield. The information in this message may be exempt from release under the Freedom of Information Act. If you received this message in error, please delete all copies and promptly notify the sender.