[boost] boost 1.30.2 thread support issue under cygwin

From: Simon J. Julier (sjulier_at_[hidden])
Date: 2003-08-23 07:34:35

I just downloaded and tried to build boost 1.30.2 under cygwin using gcc 
3.2 (20020927 (prerelease) if you want to be precise). libboost_thread.dll 
won't compile because it gives the "Thread support is unavailable!" error. 
A sample is:

===========================================================

gcc-C++-action 
libs/thread/build/bin/libboost_thread.dll/gcc/debug/runtime-link-dynamic/threading-multi/condition.o
In file included from libs/thread/src/condition.cpp:12:
/cygdrive/c/proj/nrl/main/BARS/tracking/DDF/toolkits/boost-1.30.2/boost/thread/condition.hpp:17:5: 
#error Thread support is unavailable!
In file included from libs/thread/src/condition.cpp:14:
/cygdrive/c/proj/nrl/main/BARS/tracking/DDF/toolkits/boost-1.30.2/boost/thread/thread.hpp:17:5: 
#error Thread support is unavailable!
In file included from 
/cygdrive/c/proj/nrl/main/BARS/tracking/DDF/toolkits/boost-1.30.2/boost/thread/thread.hpp:22,
                  from libs/thread/src/condition.cpp:14:
/cygdrive/c/proj/nrl/main/BARS/tracking/DDF/toolkits/boost-1.30.2/boost/thread/mutex.hpp:17:5: 
#error Thread support is unavailable!

     g++  -c -Wall -ftemplate-depth-100  -DBOOST_THREAD_BUILD_DLL=1  -g -O0 
-fno-inline -mthreads   -I"libs/thread/build"  -I 
"/cygdrive/c/proj/nrl/main/BARS/tracking/DDF/toolkits/boost-1.30.2"  -o 
"libs/thread/build/bin/libboost_thread.dll/gcc/debug/runtime-link-dynamic/threading-multi/condition.o" 
"libs/thread/build/../src/condition.cpp"

===========================================================

 From the g++ man pages, -mthreads "Support thread-safe exception handling 
on Mingw32" and only defines _MT for Mingw32. Therefore, after threading 
support is disabled on line 53 of boost/config/compiler/gcc.hpp, nothing 
actually enables it again for a non-Mingw32 cygwin build. Is this the 
desired behaviour? (If I removed the check for __CYGWIN__ in gcc.hpp, 
everything compiles and the tests seem to run correctly).

Cheers,

Simon