Update hipcc

[ROCm/hip commit: b340f4a6ed]

projects/hip/bin/hipcc

@@ -131,6 +131,7 @@ if ($HIP_PLATFORM eq "hcc") {
         $HIPCXXFLAGS .= " -stdlib=libc++";
         $setStdLib = 1;
     }
+    # Force -stdlib=libc++ on Cent OS 7
     if ($HOST_OSNAME eq "\"centos\"" and $HOST_OSVER eq "\"7\"") {
         $HIPCXXFLAGS .= " -stdlib=libc++";
         $HIPLDFLAGS .= " -lc++ -lc++abi";