Basic support for runtime in shared library.

Needs to be built with runtime/build-sharedlibs.sh and activated manually by
providing -defaultlib=llvmdc-runtime-shared -defaultlib=tango-cc-tango-shared
-defaultlib=tango-gc-basic-shared on llvmdc call at the moment.

To support D shared libraries in non-D code, we need to remove the main() from
libllvmdc-runtime-shared.

runtime/build-sharedlibs.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# I'm no good bash scripter ...
+
+# copy imports
+mkdir -p ../tango/llvmdc
+cp internal/llvmdc/bitmanip.d ../tango/llvmdc/bitmanip.di
+cp internal/llvmdc/vararg.d ../tango/llvmdc/vararg.di
+cp import/llvmdc/* ../tango/llvmdc
+
+# make the runtime
+cp -R lib ../tango
+cd ../tango/lib
+make -f llvmdc-posix.mak clean
+make -f llvmdc-posix.mak sharedlib
+cd ../..
+
+# install the runtime
+rm -f lib/libllvmdc-runtime-shared.so
+cp runtime/internal/libllvmdc-runtime-shared.so lib
+rm -f lib/libtango-gc-basic-shared.so
+cp tango/lib/gc/basic/libtango-gc-basic-shared.so lib
+rm -f lib/libtango-cc-tango-shared.so
+cp tango/lib/common/tango/libtango-cc-tango-shared.so lib