couple of AIX signals

work around a miscompilation in newer

AIX xlC does not define PRIxMAX in C++ mode, unless __STDC_FORMAT_MACROS

AIX xlc does not like struct { (name):1; }; so lose these parenthesēs

on a quest to break CHERI:

1<<LONG_WIDTH is UB, not IB/unspecified

rewort startup files section as requested by наб on Fedi

reword paragraph to avoid possible misunderstanding

• sync head and CSS for consistency

C++ allows (+(&main))…

fix buffer underrun on OS/2

[komh] Fix compilation on OS/2

Fix compilation on OS/2

duplicate strsignal(3) return values

NSIG_MAX may need <limits.h>