https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100552
--- Comment #1 from Marius Hillenbrand <mhillen at linux dot ibm.com> ---
Indeed, that line should not use the bash-specific pattern substitution and
instead like this:
diff --git a/gcc/configure.ac b/gcc/configure.ac
index e9ba2af548a..4e788019d99 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -7499,7 +7499,8 @@ case $target in
# cross build. are target headers available?
# carefully coerce the build-system compiler to use target headers
saved_CXXFLAGS="$CXXFLAGS"
- CROSS_TEST_CXXFLAGS="-nostdinc ${XGCC_FLAGS_FOR_TARGET//-B/-idirafter/}"
+ fixed_XGCC_FLAGS_FOR_TARGET=`echo "$XGCC_FLAGS_FOR_TARGET" | sed
's/-B/-idirafter/g'`
+ CROSS_TEST_CXXFLAGS="-nostdinc $fixed_XGCC_FLAGS_FOR_TARGET"
CXXFLAGS="$CROSS_TEST_CXXFLAGS"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
not fully tested yet, but it avoids the syntax error in dash and in NetBSD 9.1
