HelenOS sources

__PRINTF_FLAG_SPACESIGN   61 boot/generic/src/printf_core.c #define __PRINTF_FLAG_SPACESIGN    0x00000040
__PRINTF_FLAG_SPACESIGN   78 common/printf/printf_core.c #define __PRINTF_FLAG_SPACESIGN    0x00000040
__PRINTF_FLAG_SPACESIGN   78 kernel/generic/common/printf/printf_core.c #define __PRINTF_FLAG_SPACESIGN    0x00000040
__PRINTF_FLAG_SPACESIGN   78 uspace/lib/c/common/printf/printf_core.c #define __PRINTF_FLAG_SPACESIGN    0x00000040

HelenOS homepage, sources at GitHub