diff --git a/spec/rubyspec/optional/capi/spec_helper.rb b/spec/rubyspec/optional/capi/spec_helper.rb
index 1c16261714..f8314029c9 100644
--- a/spec/rubyspec/optional/capi/spec_helper.rb
+++ b/spec/rubyspec/optional/capi/spec_helper.rb
@@ -83,7 +83,9 @@ def compile_extension(name)
 
   ldshared  = RbConfig::CONFIG["LDSHARED"]
   ldshared += " #{RbConfig::CONFIG["ARCH_FLAG"]}" if RbConfig::CONFIG["ARCH_FLAG"]
-  libs      = "#{RbConfig::CONFIG["LIBRUBYARG"]} #{RbConfig::CONFIG["LIBS"]}"
+  libs      = RbConfig::CONFIG["LIBRUBYARG_SHARED"]
+  libs     += " " if libs
+  libs     += RbConfig::CONFIG["LIBS"]
   dldflags  = "#{RbConfig::CONFIG["LDFLAGS"]} #{RbConfig::CONFIG["DLDFLAGS"]} #{RbConfig::CONFIG["EXTDLDFLAGS"]}"
   dldflags.sub!(/-Wl,-soname,\S+/, '')
   dldflags.sub!(/\$\(DEFFILE\)/, '')