core: check if res_init requires linking with libresolv

CMakeLists.txt

@@ -208,6 +208,7 @@ include(FindPkgConfig)
 include(CheckIncludeFiles)
 include(CheckFunctionExists)
 include(CheckSymbolExists)
+include(CheckLibraryExists)
 
 check_include_files("langinfo.h" HAVE_LANGINFO_CODESET)
 check_include_files("sys/resource.h" HAVE_SYS_RESOURCE_H)
@@ -222,6 +223,16 @@ check_symbol_exists("htonll" "sys/types.h;netinet/in.h;inttypes.h" HAVE_HTONLL)
 
 check_symbol_exists("eat_newline_glitch" "term.h" HAVE_EAT_NEWLINE_GLITCH)
 
+# Check if res_init requires libresolv
+check_function_exists(res_init, LIBC_HAS_RES_INIT)
+if(NOT LIBC_HAS_RES_INIT)
+  find_library(RESOLV_LIBRARY resolv)
+  check_library_exists("${RESOLV_LIBRARY}" res_init "" LIBRESOLV_HAS_RES_INIT)
+  if(LIBRESOLV_HAS_RES_INIT)
+    list(APPEND EXTRA_LIBS ${RESOLV_LIBRARY})
+  endif()
+endif()
+
 # Check for Large File Support
 if(ENABLE_LARGEFILE)
   add_definitions(-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -D_LARGE_FILES)

src/gui/curses/CMakeLists.txt

@@ -53,11 +53,6 @@ if(ENABLE_ZSTD)
   list(APPEND EXTRA_LIBS ${LIBZSTD_LDFLAGS})
 endif()
 
-if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-  # link with resolv lib on macOS
-  list(APPEND EXTRA_LIBS "resolv")
-endif()
-
 if(ENABLE_NCURSES)
   subdirs(normal)
 endif()