Fix gen-platforms.sh build

__dso_handle.h has bene moved to bionic/libc/arch-common/bionic/__dso_handle.h
since eb847bc8666842a3cfc9c06e8458ad1abebebaf0

Change-Id: I03f6491fd44f25e7cd36e54767b26324e95dc80d
diff --git a/build/tools/gen-platforms.sh b/build/tools/gen-platforms.sh
index 6bfa00e..d709360 100755
--- a/build/tools/gen-platforms.sh
+++ b/build/tools/gen-platforms.sh
@@ -531,6 +531,7 @@
         (cd "$SRC_DIR" && $CC \
                  -I$SRCDIR/../../bionic/libc/include \
                  -I$SRCDIR/../../bionic/libc/private \
+                 -I$SRCDIR/../../bionic/libc/arch-common/bionic \
                  -I$SRCDIR/../../bionic/libc/arch-$ARCH/include \
                  -isystem $SRCDIR/../../bionic/libc/kernel/common \
                  -isystem $SRCDIR/../../bionic/libc/kernel/common/linux \