Tweak GCC's inlining parameters to get thread_obj inlined

rts/Makefile

@@ -317,6 +317,9 @@ endif
 # -O3 helps unroll some loops (especially in copy() with a constant argument).
 GC_HC_OPTS += -optc-O3
 
+# Without this, thread_obj will not be inlined (at least on x86 with GCC 4.1.0)
+GCCompact_HC_OPTS += -optc-finline-limit=2500
+
 # -fno-strict-aliasing is required for the runtime, because we often
 # use a variety of types to represent closure pointers (StgPtr,
 # StgClosure, StgMVar, etc.), and without -fno-strict-aliasing gcc is