Add bind_at_load compiler flag to force symbol binding

Attempt to fix deadlock due to symbol binding, which takes a global lock loading a dylib, when running gc collection if another thread was stopped while holding the global lock.

mono/mini/Makefile.am.in

@@ -771,7 +771,7 @@ libmonoboehm_2_0_la_LIBADD = libmini.la $(interp_libs_with_mini) $(dbg_libs_with
 libmonoboehm_2_0_la_LDFLAGS = $(libmonoldflags) $(monobin_platform_ldflags) 
 
 libmonosgen_2_0_la_SOURCES =
-libmonosgen_2_0_la_CFLAGS = $(mono_sgen_CFLAGS) @CXX_ADD_CFLAGS@
+libmonosgen_2_0_la_CFLAGS = $(mono_sgen_CFLAGS) @CXX_ADD_CFLAGS@ -Xcompiler -bind_at_load
 
 libmonosgen_2_0_la_LIBADD = libmini.la $(interp_libs_with_mini) $(dbg_libs_with_mini) $(sgen_libs) $(LIBMONO_DTRACE_OBJECT) $(LLVMMONOF)
 libmonosgen_2_0_la_LDFLAGS = $(libmonoldflags) $(monobin_platform_ldflags)