Userspace RCU

liburcu fail to compile properly on Mac OSX. For some yet unknown reason, configure detect that the CPU type used on these machines as a 386 which is quite wrong.

Compile fail with:

$ make
make  all-recursive
Making all in .
  CC     wfqueue.lo
  CC     wfstack.lo
  CC     compat_arch_x86.lo
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:44:suffix
or operands invalid for `pushf'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:44:suffix
or operands invalid for `pop'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:55:suffix
or operands invalid for `push'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:55:suffix
or operands invalid for `popf'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:60:suffix
or operands invalid for `pushf'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:60:suffix
or operands invalid for `pop'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:65:suffix
or operands invalid for `push'
/var/folders/9f/pv25pv1j7k54m9q11sz79w0h0000gn/T//cc2LG2nk.s:65:suffix
or operands invalid for `popf'
make[2]: *** [compat_arch_x86.lo] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

Relevant config.log:

Kernel configured for up to 2 processors.
2 processors are physically available.
2 processors are logically available.
Processor type: i486 (Intel 80486)

[...]

## ----------- ##
## Core tests. ##
## ----------- ##

configure:2319: checking build system type
configure:2333: result: i386-apple-darwin12.4.0
configure:2353: checking host system type
configure:2366: result: i386-apple-darwin12.4.0
configure:2386: checking target system type
configure:2399: result: i386-apple-darwin12.4.0

[...]

configure:3401: gcc -v >&5
Using built-in specs.
Target: i686-apple-darwin11

Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/src/configure --disable-checking --enable-werror --prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2 --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib --build=i686-apple-darwin11 --enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/dst-llvmCore/Developer/usr/local --program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 --target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)

Forcing the configure build flag could work around this issue:
./configure --build=x86_64-apple-darwin11

References:
https://trac.macports.org/ticket/21011