Fix missing unlock.
Fix missing unlock.

Submitted by:	Nick Tuckett


davidchisnall/libobjc2,gnustep/libobjc2,darlinghq/darling-libobjc2,ngrewe/libobjc2,ngrewe/libobjc2,darlinghq/darling-libobjc2,gnustep/libobjc2,crystax/android-vendor-libobjc2,davidchisnall/libobjc2,crystax/android-vendor-libobjc2