[CMake] Use append for CMAKE_REQUIRED_* variables

This ensures that required includes and libraries such as -lm that
were added earlier aren't overwritten.

Differential Revision: https://reviews.llvm.org/D88068

diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index eeaebf31c926ff8143ab8fd902aeb753807bd894..797485e3d024ae55a2786c89c69486700fcf12d2 100644 (file)
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -126,8 +126,8 @@ if(LLVM_ENABLE_ZLIB)
     # Check if zlib we found is usable; for example, we may have found a 32-bit
     # library on a 64-bit system which would result in a link-time failure.
     cmake_push_check_state()
-    set(CMAKE_REQUIRED_INCLUDES ${ZLIB_INCLUDE_DIRS})
-    set(CMAKE_REQUIRED_LIBRARIES ${ZLIB_LIBRARY})
+    list(APPEND CMAKE_REQUIRED_INCLUDES ${ZLIB_INCLUDE_DIRS})
+    list(APPEND CMAKE_REQUIRED_LIBRARIES ${ZLIB_LIBRARY})
     check_symbol_exists(compress2 zlib.h HAVE_ZLIB)
     cmake_pop_check_state()
     if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON AND NOT HAVE_ZLIB)
@@ -147,8 +147,8 @@ if(LLVM_ENABLE_LIBXML2)
     # Check if libxml2 we found is usable; for example, we may have found a 32-bit
     # library on a 64-bit system which would result in a link-time failure.
     cmake_push_check_state()
-    set(CMAKE_REQUIRED_INCLUDES ${LIBXML2_INCLUDE_DIRS})
-    set(CMAKE_REQUIRED_LIBRARIES ${LIBXML2_LIBRARIES})
+    list(APPEND CMAKE_REQUIRED_INCLUDES ${LIBXML2_INCLUDE_DIRS})
+    list(APPEND CMAKE_REQUIRED_LIBRARIES ${LIBXML2_LIBRARIES})
     check_symbol_exists(xmlReadMemory libxml/xmlreader.h HAVE_LIBXML2)
     cmake_pop_check_state()
     if(LLVM_ENABLE_LIBXML2 STREQUAL FORCE_ON AND NOT HAVE_LIBXML2)