[gentoo-user] Unable to install the ffi gem.

[Vishnupradeep]

x86_64-pc-linux-gnu-gcc -I. -I. -I/usr/lib64/ruby/1.8/x86_64-linux -I.
-DRUBY_EXTCONF_H=\"extconf.h\"    -fPIC -march=amdfam10 -O2 -pipe
-fno-strict-aliasing  -fPIC  -I/usr/lib64/libffi-3.0.10/include
-Wno-declaration-after-statement   -c Struct.c
x86_64-pc-linux-gnu-gcc -I. -I. -I/usr/lib64/ruby/1.8/x86_64-linux -I.
-DRUBY_EXTCONF_H=\"extconf.h\"    -fPIC -march=amdfam10 -O2 -pipe
-fno-strict-aliasing  -fPIC  -I/usr/lib64/libffi-3.0.10/include
-Wno-declaration-after-statement   -c DataConverter.c
x86_64-pc-linux-gnu-gcc -shared -o ffi_c.so Function.o Pointer.o Buffer.o
AbstractMemory.o ArrayType.o ffi.o MappedType.o StructByValue.o Call.o
StructLayout.o Thread.o Platform.o Variadic.o MethodHandle.o MemoryPointer.o
Types.o DynamicLibrary.o Type.o ClosurePool.o FunctionInfo.o LastError.o
StructByReference.o Struct.o DataConverter.o -L. -L/usr/lib64
-Wl,-R/usr/lib64 -L. -Wl,-O1 -Wl,--as-needed -rdynamic -Wl,-export-dynamic
-Wl,--no-undefined     -Wl,-R -Wl,/usr/lib64 -L/usr/lib64 -lruby18 -lffi
 -lffi   -lrt -ldl -lcrypt -lm   -lc
Thread.o: In function `cleanup_blocking_thread':
Thread.c:(.text+0x29): undefined reference to `pthread_kill'
Thread.o: In function `rbffi_blocking_thread':
Thread.c:(.text+0xd9): undefined reference to `pthread_testcancel'
Thread.o: In function `rbffi_thread_blocking_region':
Thread.c:(.text+0x1ef): undefined reference to `pthread_create'
Thread.c:(.text+0x225): undefined reference to `pthread_join'
collect2: ld returned 1 exit status
make: *** [ffi_c.so] Error 1


Gem files will remain installed in /usr/lib64/ruby/gems/1.8/gems/ffi-1.0.9
for inspection.
Results logged to
/usr/lib64/ruby/gems/1.8/gems/ffi-1.0.9/ext/ffi_c/gem_make.out
tux diaspora #