+# A patch discussed here:
+# https://gcc.gnu.org/ml/gcc-patches/2014-06/msg02185.html
+# introduces spurious #line markers into the preprocessor output. The result
+# appears in gcc 5.0 and (with modification) in 5.1, making it necessary to
+# determine if we are using gcc, and if so, what version because the proposed
+# solution uses a nonstandard option.
+PRG=`echo "$1" | $AWK '{ sub(/^[ ]*/,""); sub(/[ ].*$/, ""); print; }' || exit 0`
+FSF=`("$PRG" --version 2>/dev/null || exit 0) | fgrep "Free Software Foundation" | head -n 1`
+ALL=`"$PRG" -dumpversion 2>/dev/null || exit 0`
+ONE=`echo "$ALL" | sed -e 's/\..*$//'`
+if test -n "$FSF" && test -n "$ALL" && test -n "$ONE" ; then
+ if test $ONE -ge 5 ; then
+ echo ".. adding -P option to work around $PRG $ALL" >&2
+ preprocessor="$preprocessor -P"
+ fi
+fi
+