Index: VirtualBox-5.1.16/src/libs/libxml2-2.9.4/libxml.spec.in
===================================================================
--- VirtualBox-5.1.16.orig/src/libs/libxml2-2.9.4/libxml.spec.in
+++ VirtualBox-5.1.16/src/libs/libxml2-2.9.4/libxml.spec.in
@@ -94,7 +94,7 @@ at parse time or later once the document
 
 %build
 %configure
-make %{_smp_mflags}
+make
 
 %install
 rm -fr %{buildroot}
Index: VirtualBox-5.1.16/src/libs/libxml2-2.9.4/libxml2.spec
===================================================================
--- VirtualBox-5.1.16.orig/src/libs/libxml2-2.9.4/libxml2.spec
+++ VirtualBox-5.1.16/src/libs/libxml2-2.9.4/libxml2.spec
@@ -94,7 +94,7 @@ at parse time or later once the document
 
 %build
 %configure
-make %{_smp_mflags}
+make
 
 %install
 rm -fr %{buildroot}