[CMake] Move find_package(ZLIB) to LLVMConfig

This way, downstream projects don't have to invoke find_package(ZLIB)
reducing the amount of boilerplate.

Differential Revision: https://reviews.llvm.org/D84691

clang/CMakeLists.txt

@@ -114,10 +114,6 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
   option(CLANG_ENABLE_BOOTSTRAP "Generate the clang bootstrap target" OFF)
   option(LLVM_ENABLE_LIBXML2 "Use libxml2 if available." ON)
 
-  if(LLVM_ENABLE_ZLIB)
-    find_package(ZLIB)
-  endif()
-
   include(AddLLVM)
   include(TableGen)
   include(HandleLLVMOptions)

lld/CMakeLists.txt

@@ -51,10 +51,6 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
 
-  if(LLVM_ENABLE_ZLIB)
-    find_package(ZLIB)
-  endif()
-
   include(AddLLVM)
   include(TableGen)
   include(HandleLLVMOptions)

lldb/cmake/modules/LLDBStandalone.cmake

@@ -74,10 +74,6 @@ endif()
 # CMake modules to be in that directory as well.
 list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
-if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB)
-endif()
-
 include(AddLLVM)
 include(TableGen)
 include(HandleLLVMOptions)

llvm/cmake/modules/LLVMConfig.cmake.in

@@ -50,6 +50,9 @@ set(LLVM_ENABLE_THREADS @LLVM_ENABLE_THREADS@)
 set(LLVM_ENABLE_UNWIND_TABLES @LLVM_ENABLE_UNWIND_TABLES@)
 
 set(LLVM_ENABLE_ZLIB @LLVM_ENABLE_ZLIB@)
+if(LLVM_ENABLE_ZLIB)
+  find_package(ZLIB)
+endif()
 
 set(LLVM_LIBXML2_ENABLED @LLVM_LIBXML2_ENABLED@)
 

mlir/examples/standalone/CMakeLists.txt

@@ -29,10 +29,6 @@ set(MLIR_BINARY_DIR ${CMAKE_BINARY_DIR})
 list(APPEND CMAKE_MODULE_PATH "${MLIR_CMAKE_DIR}")
 list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
 
-if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB)
-endif()
-
 include(TableGen)
 include(AddLLVM)
 include(AddMLIR)