Add an LLVM patch to fix the windows build breakage from #18490 (#18538)

create DestSharedLibDir in the LLVM Makefile

Author: tkelman

deps/llvm.mk

@@ -432,6 +432,7 @@ $(eval $(call LLVM_PATCH,llvm-D14260))
 $(eval $(call LLVM_PATCH,llvm-nodllalias))
 $(eval $(call LLVM_PATCH,llvm-D21271-instcombine-tbaa-3.7))
 $(eval $(call LLVM_PATCH,llvm-win64-reloc-dwarf))
+$(eval $(call LLVM_PATCH,llvm-3.7.1_destsharedlibdir))
 else ifeq ($(LLVM_VER_SHORT),3.8)
 ifeq ($(LLVM_VER),3.8.0)
 $(eval $(call LLVM_PATCH,llvm-D17326_unpack_load))

deps/patches/llvm-3.7.1_destsharedlibdir.patch

@@ -0,0 +1,14 @@
+diff --git a/Makefile.rules b/Makefile.rules
+index 24cac3b..4f52dbb 100644
+--- a/Makefile.rules
++++ b/Makefile.rules
+@@ -1234,6 +1234,9 @@ endif
+ DestSharedLib := $(DestSharedLibDir)/$(BaseLibName.SO)
+ DestSharedAlias := $(DestSharedLibDir)/$(BaseAliasName.SO)
+ 
++$(DestSharedLibDir)::
++	$(MKDIR) $(DestSharedLibDir)
++
+ install-local:: $(DestSharedLib)
+ 
+ $(DestSharedLib): $(LibName.SO) $(DestSharedLibDir)