[DRE-maint] Bug#848660: ruby: might need to strip -fdebug-prefix-map

[Chris Hofstaedtler]

Hi Chris,

* Chris Lamb <lamby at debian.org> [190211 22:53]:
> > dpkg-buildflags has started injecting -fdebug-prefix-map with a
> > variable path into C(..)FLAGS. We need to figure out if we need to
> > strip that.
> 
> Strip it? As in, the output of CFLAGS ends up in the build...?

Indeed:

$ irb
irb(main):001:0> RbConfig::CONFIG['CFLAGS']
=> "-g -O2 -fdebug-prefix-map=/build/ruby2.3-TqM27i/ruby2.3-2.3.3=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC"

AFAIK the popular extension building mechanisms (mkmf et al) use this
to discover the required build flags when compiling native extensions.
Maybe it does not matter in practice, but that is part of "figuring
it out" :-)

Best,
Chris