cmake: Fix detection of a fully seperate libresolv

With glibc 2.24 all res_* symbols moved from libresolv to libc. This means
that socket_wrapper is not able to do the traffic to the DNS server. This
leaves us only with DNS faking.

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index 84442321127b76134b11517e517588ad3c2261f8..6eb00daabc72fc5681ecc1c3b564cff36853ddd9 100644 (file)
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -57,12 +57,23 @@ check_function_exists(getexecname HAVE_GETEXECNAME)
 
 find_library(RESOLV_LIRBRARY resolv)
 if (RESOLV_LIRBRARY)
-    set(HAVE_LIBRESOLV TRUE)
+    check_function_exists(res_nquery HAVE_LIBC_RES_INIT)
+    check_function_exists(__res_query HAVE_LIBC__RES_INIT)
+
+    if (NOT HAVE_LIBC_RES_INIT AND NOT HAVE_LIBC__RES_INIT)
+        set(CMAKE_REQUIRED_LIBRARIES ${RESOLV_LIRBRARY})
+        check_function_exists(res_query HAVE_RES_QUERY)
+        check_function_exists(__res_query HAVE___RES_QUERY)
+        unset(CMAKE_REQUIRED_LIBRARIES)
+
+        if (HAVE_RES_QUERY OR HAVE___RES_QUERY)
+            set(HAVE_LIBRESOLV 1)
+
+        endif()
+    endif()
 
     # If we have a libresolv, we need to check functions linking the library
     list(APPEND _REQUIRED_LIBRARIES ${RESOLV_LIRBRARY})
-else()
-    message(STATUS "libresolv not found on ${CMAKE_SYSTEM_NAME}: Only dns faking will be available")
 endif()
 
 set(CMAKE_REQUIRED_LIBRARIES ${RESOLV_LIRBRARY})
@@ -205,4 +216,8 @@ int main(void) {
 # ENDIAN
 test_big_endian(WORDS_BIGENDIAN)
 
+if (NOT HAVE_LIBRESOLV)
+    message(STATUS "Limited features: Only dns faking will be available")
+endif()
+
 set(RWRAP_REQUIRED_LIBRARIES ${_REQUIRED_LIBRARIES} CACHE INTERNAL "resolv_wrapper required system libraries")