mu: add soft dependency on json-glib

If it's available it will be used.

configure.ac

@@ -164,6 +164,17 @@ AC_SUBST(GMIME_LIBS)
 gmime_version="`$PKG_CONFIG --modversion gmime-3.0`"
 
 
+# gmime, version 3.0 or higher
+PKG_CHECK_MODULES(JSON_GLIB,json-glib-1.0 >= 1.4,[have_json_glib=yes],[have_json_glib=no])
+AS_IF([test "x$have_json_glib" = "xyes"],[
+  AC_SUBST(JSON_GLIB_CFLAGS)
+  AC_SUBST(JSON_GLIB_LIBS)
+  json_glib_version="$($PKG_CONFIG --modversion json-glib-1.0)"
+  AC_DEFINE(HAVE_JSON_GLIB,[1], [Do we support json-glib?])
+])
+AM_CONDITIONAL(HAVE_JSON_GLIB,[test "x$have_json_glib" = "xyes"])
+
+
 # xapian checking - we need 1.2.x at least
 AC_CHECK_PROG(XAPIAN_CONFIG,xapian-config,xapian-config,no)
 AM_CONDITIONAL(HAVE_XAPIAN,test "x$XAPIAN_CONFIG" != "xno")
@@ -318,6 +329,10 @@ echo "Xapian version                       : $xapian_version"
 echo "GLib version                         : $glib_version"
 echo "GMime version                        : $gmime_version"
 
+AM_COND_IF([HAVE_JSON_GLIB],[
+echo "Json-Glib version                    : $json_glib_version"
+])
+
 AM_COND_IF([BUILD_GUI],[
 echo "GTK+ version                         : $gtk_version"
 echo "Webkit version                       : $webkit_version"

lib/Makefile.am

@@ -20,12 +20,21 @@ include $(top_srcdir)/gtest.mk
 # before decending into tests/
 SUBDIRS= parser . tests
 
+if HAVE_JSON_GLIB
+json_srcs=					\
+	mu-msg-json.c				\
+	mu-msg-json.h
+json_flag="-DHAVE_JSON_GLIB"
+endif
+
 AM_CFLAGS=					\
 	$(WARN_CFLAGS)				\
 	$(GMIME_CFLAGS)				\
 	$(GLIB_CFLAGS)				\
 	$(GUILE_CFLAGS)				\
+	$(JSON_GLIB_CFLAGS)			\
 	$(ASAN_CFLAGS)				\
+	$(json_flag)				\
 	-Wno-format-nonliteral			\
 	-Wno-switch-enum			\
 	-Wno-suggest-attribute=format		\
@@ -36,6 +45,7 @@ AM_CXXFLAGS=					\
 	$(WARN_CXXFLAGS)			\
 	$(GMIME_CFLAGS)				\
 	$(GLIB_CFLAGS)				\
+	$(JSON_GLIB_CFLAGS)			\
 	$(XAPIAN_CXXFLAGS)			\
 	$(GUILE_CFLAGS)				\
 	$(ASAN_CXXFLAGS)
@@ -76,6 +86,7 @@ libmu_la_SOURCES=				\
 	mu-msg-file.h				\
 	mu-msg-iter.cc				\
 	mu-msg-iter.h				\
+	$(json_srcs)				\
 	mu-msg-part.c				\
 	mu-msg-part.h				\
 	mu-msg-prio.c				\
@@ -108,6 +119,7 @@ libmu_la_LIBADD=				\
 	$(GMIME_LIBS)				\
 	$(GLIB_LIBS)				\
 	$(GUILE_LIBS)				\
+	$(JSON_GLIB_LIBS)			\
 	${builddir}/parser/libmuxparser.la
 
 libmu_la_LDFLAGS=				\

lib/tests/Makefile.am

@@ -32,6 +32,7 @@ AM_CPPFLAGS=$(XAPIAN_CXXFLAGS)					\
 # use -Wno-unused-parameters, because some callbacks may not
 # really need all the params they get
 AM_CFLAGS=							\
+	$(JSON_GLIB_CFLAGS)					\
 	$(WARN_CFLAGS)						\
 	$(ASAN_CFLAGS)
 AM_CXXFLAGS=							\

mu/Makefile.am

@@ -26,6 +26,7 @@ AM_CPPFLAGS=-I${top_srcdir}/lib $(GLIB_CFLAGS)
 # use -Wno-unused-parameters, because some callbacks may not
 # really need all the params they get
 AM_CFLAGS=						\
+	$(JSON_GLIB_CFLAGS)				\
 	$(ASAN_CFLAGS)					\
 	$(WARN_CFLAGS)					\
 	-Wno-switch-enum				\