configure: Identify icc compiler with a less ambiguous pattern

diff --git a/configure b/configure
index 52cebb7c634ca434a513fd91c6af1f5d04c01397..df1a01c20a206ce40a0537c823d031c28ba362be 100755 (executable)
--- a/configure
+++ b/configure
@@ -2364,7 +2364,7 @@ probe_cc(){
         fi
         _cflags_speed='-O3'
         _cflags_size='-Os'
-    elif $_cc --version 2>/dev/null | grep -q Intel; then
+    elif $_cc --version 2>/dev/null | grep -q ^icc; then
         _type=icc
         _ident=$($_cc --version | head -n1)
         _depflags='-MMD'