clover: Require libelf

v2: test for libelf once, check in both radeon and clover

CC: Tom Stellard <tom@stellard.net>
CC: Emil Velikov <emil.l.velikov@gmail.com>
CC: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/configure.ac b/configure.ac
index 09a71b7..03f1bca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1465,6 +1465,7 @@
    [CLANG_LIBDIR=''])
 
 PKG_CHECK_EXISTS([libclc], [have_libclc=yes], [have_libclc=no])
+AC_CHECK_LIB([elf], [elf_memory], [have_libelf=yes;ELF_LIB=-lelf])
 
 if test "x$enable_opencl" = xyes; then
     if test -z "$with_gallium_drivers"; then
@@ -1495,6 +1496,10 @@
     else
         OPENCL_LIBNAME="OpenCL"
     fi
+
+    if test "x$have_libelf" != xyes; then
+       AC_MSG_ERROR([Clover requires libelf])
+    fi
 fi
 AM_CONDITIONAL(HAVE_CLOVER, test "x$enable_opencl" = xyes)
 AM_CONDITIONAL(HAVE_CLOVER_ICD, test "x$enable_opencl_icd" = xyes)
@@ -1870,8 +1875,9 @@
     fi
     LLVM_COMPONENTS="${LLVM_COMPONENTS} r600 bitreader ipo"
     NEED_RADEON_LLVM=yes
-    AC_CHECK_LIB([elf], [elf_memory], [ELF_LIB=-lelf],
-                                 [AC_MSG_ERROR([$1 requires libelf when using LLVM])])
+    if test "x$have_libelf" != xyes; then
+       AC_MSG_ERROR([$1 requires libelf when using llvm])
+    fi
 }
 
 dnl Duplicates in GALLIUM_DRIVERS_DIRS are removed by sorting it after this block