Silence useless icc warnings.

Originally committed as revision 13118 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1815,6 +1815,20 @@ fi
 check_cflags -fno-math-errno
 check_cflags -fno-signed-zeros
 
+# add some flags for Intel C Compiler
+if $cc --version | grep -q Intel; then
+  # Just warnings, no remarks
+  check_cflags -w1
+  # -wd: Disable following warnings
+  # 144, 167, 556: -Wno-pointer-sign
+  # 10006: ignoring unknown option -fno-signed-zeros
+  # 10156: ignoring option '-W'; no argument required
+  check_cflags -wd144,167,556,10006,10156
+  # 11030: Warning unknown option --as-needed
+  # 10156: ignoring option '-export'; no argument required
+  check_ldflags -wd10156,11030
+fi
+
 # PIC flags for shared library objects where they are needed
 if enabled shared; then
     # LIBOBJFLAGS may have already been set in the OS configuration