[ORC] Fix the prototype of a C API function.

[maleadt]

In 38d16f5, the TargetTriple argument was removed from the LLVMOrcCreateStaticLibrarySearchGeneratorForPath without updating the C API headers. This results in the function being exported without C linkage, making it impossible to use from C.

Before 38d16f5:

❯ objdump -t bisect/lib/libLLVMOrcJIT.so | grep LLVMOrcCreateStaticLibrarySearchGeneratorForPath 
00000000001502b0 g     F .text  000000000000021c              LLVMOrcCreateStaticLibrarySearchGeneratorForPath

After 38d16f5:

❯ objdump -t bisect/lib/libLLVMOrcJIT.so | grep LLVMOrcCreateStaticLibrarySearchGeneratorForPath 
000000000014ff30 g     F .text  00000000000000de              _Z48LLVMOrcCreateStaticLibrarySearchGeneratorForPathPP32LLVMOrcOpaqueDefinitionGeneratorP24LLVMOrcOpaqueObjectLayerPKc

cc @lhames

[lhames]

@llvm-ci please test