[libsecret] build: Use $-quoted string to escape newline

[Stefan Walter <stefw src gnome org>]

commit 4d7b190b67e882a8c9e1fe7b23cf6e8b1aeb9e17
Author: Philip Chimento <philip chimento gmail com>
Date:   Tue Feb 16 21:55:20 2016 -0800

    build: Use $-quoted string to escape newline
    
    BSD sed doesn't like escaping a literal newline character with a
    backslash. Instead, use a $-quoted string to escape the newline as \n.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734630

 libsecret/Makefile.am |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/libsecret/Makefile.am b/libsecret/Makefile.am
index 07bbad6..0157b3f 100644
--- a/libsecret/Makefile.am
+++ b/libsecret/Makefile.am
@@ -89,8 +89,7 @@ temp-dbus-generated.c: $(DBUS_XML_DEFINITIONS) Makefile.am
        $(AM_V_GEN) gdbus-codegen --interface-prefix org.freedesktop.Secret. \
                --generate-c-code temp-dbus-generated --c-namespace SecretGen $<
 secret-dbus-generated.c: temp-dbus-generated.c Makefile.am
-       $(AM_V_GEN) sed -e '1i\
-       #define GLIB_DISABLE_DEPRECATION_WARNINGS' \
+       $(AM_V_GEN) sed -e $$'1i\\\n#define GLIB_DISABLE_DEPRECATION_WARNINGS' \
                -e 's/secret_gen_/_secret_gen_/g' -e 's/type-/type/g' \
                -e 's/temp-dbus-generated.h/secret-dbus-generated.h/g' \
                temp-dbus-generated.c > secret-dbus-generated.c