configure: Allow command line override of toolchain

Easy way to build for both gcc and clang.

Signed-off-by: David Ahern <dsahern@kernel.org>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/configure b/configure
index 8ddff43c6a7dad405ad0cd6318c05408bd625c09..13f2d1739b99b1ef46578fe01b34560e0d605efd 100755 (executable)
--- a/configure
+++ b/configure
@@ -19,10 +19,10 @@ check_toolchain()
     : ${AR=ar}
     : ${CC=gcc}
     : ${YACC=bison}
-    echo "PKG_CONFIG:=${PKG_CONFIG}" >>$CONFIG
-    echo "AR:=${AR}" >>$CONFIG
-    echo "CC:=${CC}" >>$CONFIG
-    echo "YACC:=${YACC}" >>$CONFIG
+    echo "PKG_CONFIG?=${PKG_CONFIG}" >>$CONFIG
+    echo "AR?=${AR}" >>$CONFIG
+    echo "CC?=${CC}" >>$CONFIG
+    echo "YACC?=${YACC}" >>$CONFIG
 }
 
 check_atm()