Merge #175: configure: Check compile+link when checking existence of …

…functions

79472c7 configure: Check compile+link when checking existence of functions (Tim Ruffing)

Pull request description:

ACKs for top commit:
  jonasnick:
    ACK 79472c7

Tree-SHA512: 947f794138636390d74366d9d06eb18f315f038a8555d1057c407f5592f1bd432a74c94ab758a85a5d8324908f46656518ebce30124f56a9d9c3936d144789ae

configure.ac

@@ -261,13 +261,13 @@ else
 fi
 
 AC_MSG_CHECKING([for __builtin_popcount])
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([[void myfunc() {__builtin_popcount(0);}]])],
+AC_LINK_IFELSE([AC_LANG_SOURCE([[void myfunc() {__builtin_popcount(0);}]])],
     [ AC_MSG_RESULT([yes]);AC_DEFINE(HAVE_BUILTIN_POPCOUNT,1,[Define this symbol if __builtin_popcount is available]) ],
     [ AC_MSG_RESULT([no])
     ])
 
 AC_MSG_CHECKING([for  __builtin_clzll])
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([[void myfunc() { __builtin_clzll(1);}]])],
+AC_LINK_IFELSE([AC_LANG_SOURCE([[void myfunc() { __builtin_clzll(1);}]])],
     [ AC_MSG_RESULT([yes]);AC_DEFINE(HAVE_BUILTIN_CLZLL,1,[Define this symbol if  __builtin_clzll is available]) ],
     [ AC_MSG_RESULT([no])
     ])