[llvm-c] Remove LLVMContextSetOpaquePointers

[nikic]

I think it may make sense to keep this one for now. It can also be used to force-enable opaque pointers (avoid the auto-detection for bitcode).

[nikic]

LGTM, now that LLVM 16 has branched.

llvm/docs/OpaquePointers.rst

opaque pointer transition::
     LLVMConstGEP -> LLVMConstGEP2
     LLVMConstInBoundsGEP -> LLVMConstInBoundsGEP2
     LLVMAddAlias -> LLVMAddAlias2
 
 Additionally, it will no longer be possible to call ``LLVMGetElementType()``
 on a pointer type.
 
 It is possible to control whether opaque pointers are used (if you want to
-override the default) using ``LLVMContext::setOpaquePointers`` or
-``LLVMContextSetOpaquePointers()``.
+override the default) using ``LLVMContext::setOpaquePointers``.
 
 Transition State
 ================
 
 As of April 2022 both LLVM and Clang have complete support for opaque pointers,
 and opaque pointers are enabled by default in LLVM and Clang.
 
 For users of the clang driver interface, it is possible to temporarily restore

llvm/docs/ReleaseNotes.rst

* The following deprecated functions have been removed, because they are
   * ``LLVMBuildGEP`` -> ``LLVMBuildGEP2``
   * ``LLVMBuildInBoundsGEP`` -> ``LLVMBuildInBoundsGEP2``
   * ``LLVMBuildStructGEP`` -> ``LLVMBuildStructGEP2``
   * ``LLVMBuildPtrDiff`` -> ``LLVMBuildPtrDiff2``
   * ``LLVMConstGEP`` -> ``LLVMConstGEP2``
   * ``LLVMConstInBoundsGEP`` -> ``LLVMConstInBoundsGEP2``
   * ``LLVMAddAlias`` -> ``LLVMAddAlias2``
 
+* ``LLVMContextSetOpaquePointers``, a temporary API to pin to legacy typed
+  pointer, has been removed.
+
 Changes to the Go bindings
 --------------------------
 
 
 Changes to the FastISel infrastructure
 --------------------------------------
 
 * ...

llvm/include/llvm-c/Core.h

  * If true, only the names of GlobalValue objects will be available in the IR.
  * This can be used to save memory and runtime, especially in release mode.
  *
  * @see LLVMContext::setDiscardValueNames()
  */
 void LLVMContextSetDiscardValueNames(LLVMContextRef C, LLVMBool Discard);
 
 /**
- * Set whether the given context is in opaque pointer mode.
- *
- * @see LLVMContext::setOpaquePointers()
- */
-void LLVMContextSetOpaquePointers(LLVMContextRef C, LLVMBool OpaquePointers);
-
-/**
  * Destroy a context instance.
  *
  * This should be called for every call to LLVMContextCreate() or memory
  * will be leaked.
  */
 void LLVMContextDispose(LLVMContextRef C);
 
 /**

llvm/lib/IR/Core.cpp

 LLVMBool LLVMContextShouldDiscardValueNames(LLVMContextRef C) {
   return unwrap(C)->shouldDiscardValueNames();
 }
 
 void LLVMContextSetDiscardValueNames(LLVMContextRef C, LLVMBool Discard) {
   unwrap(C)->setDiscardValueNames(Discard);
 }
 
-void LLVMContextSetOpaquePointers(LLVMContextRef C, LLVMBool OpaquePointers) {
-  unwrap(C)->setOpaquePointers(OpaquePointers);
-}
-
 void LLVMContextDispose(LLVMContextRef C) {
   delete unwrap(C);
 }
 
 unsigned LLVMGetMDKindIDInContext(LLVMContextRef C, const char *Name,
                                   unsigned SLen) {
   return unwrap(C)->getMDKindID(StringRef(Name, SLen));
 }