This reverts commit caf6150e97.
getaddrinfo_a has a nasty tendency to segfault internally in its
background thread, on every version of glibc I tested, especially
under helgrind.
See https://sourceware.org/bugzilla/show_bug.cgi?id=20874
Github-Pull: #9229
Rebased-From: 10ae7a7b2316f8052ec58ef237ce6dd987300900
OBJCXX's std flags don't get defined by our cxx macro. Rather than hard-coding
to c++11, just force OBJCXX to be the same as CXX unless the user specified
otherwise.
We don't use any elliptic curves from OpenSSL anymore, nor include this
header anywhere but optionally in the tests of secp256k1 (which has
its own autoconf setup).
Reported by sinetek on IRC.
- guard PKG_PROG_PKG_CONFIG with an m4_ifdef. If not building for windows,
require it
- add nops as necessary in case the ifdef reduces the if/then to nothing
- AC_SUBST some missing _LIBS. These were split out over time, but not all were
properly substituted. They continued to work if pkg-config is installed
because it does the AC_SUBST itself
Disabling warnings can be tricky, because doing so can cause a different
compiler to create new warnings about unsupported disable flags. Also, some
warnings don't surface until they're paired with another warning (gcc). For
example, adding "-Wno-foo" won't cause any trouble, but if there's a legitimate
warning emitted, the "unknown option -Wno-foo" will show up as well.
Work around this in 2 ways:
1. When checking to see if -Wno-foo is supported, check for "-Wfoo" instead.
2. Enable -Werror while checking 1.
If "-Werror -Wfoo" compiles, "-Wno-foo" is almost guaranteed to be supported.
-Werror itself is also checked. If that fails to compile by itself, it likely
means that the user added a flag that adds a warning. In that case, -Werror
won't be used while checking, and the build may be extra noisy. The user would
need to fix the bad input flag.
Also, silence 2 more additional warnings that can show up post-c++11.
Due to include ordering, defining in one place was not enough to ensure correct
usage. Use global defines so that we don't have to worry abou this ordering.
Also add a comment in configure about the test.
This is ugly, but temporary. boost::filesystem will likely be dropped soon
after c++11 is enabled. Otherwise, we could simply roll our own copy_file. I've
fixed this at the buildsystem level for now in order to avoid mixing in
functional changes.
Explanation:
If boost (prior to 1.57) was built without c++11, it emulated scoped enums
using c++98 constructs. Unfortunately, this implementation detail leaked into
the abi. This was fixed in 1.57.
When building against that installed version using c++11, the headers pick up
on the native c++11 scoped enum support and enable it, however it will fail to
link. This can be worked around by disabling c++11 scoped enums if linking will
fail.
Add an autoconf test to determine incompatibility. At build-time, if native
enums are being used (a c++11 build), and force-disabling them causes a
successful link, we can be sure that there's an incompatibility and enable the
work-around.
