I've switched over to using a few gnulib modules in GNU make.
I've just noticed that whenever I run configure, even though I'm on a
GNU/Linux system with GNU libc 2.27 and a fairly modern GCC 7.3, the
configure script insists on generating local copies of standard header
files:
lib/alloca.h
lib/stdlib.h
lib/sys/types.h
lib/unistd.h
Why do local copies of these files get generated on my (ostensibly
modern and compliant) system?
I attempted to decipher the configure scripting around these headers
but gave up and went to bed. I did discover that for alloca.h, if we
see the __GNUC__ preprocessor value set we apparently ALWAYS choose the
local implementation and never the default implementation:
#if defined __GNUC__ || defined _AIX || defined _MSC_VER
Need own alloca
#endif
That seems very strange to me!
The other headers I didn't make much headway on.
Any info would be interesting to me, thanks!
