libdpkg, dpkg-deb: Fix compound literal usage with C99 compilers

We cannot portably assign a compound literal to a static variable,
as the expression is not constant. GCC accepts these for backwards
compatibility in its C89 mode, but not in its C99 mode.

debian/changelog

@@ -72,6 +72,8 @@ dpkg (1.17.7) UNRELEASED; urgency=low
     This will allow non-GNU systems to easily use another value for their
     GNU tar, which is usually either gnutar or gtar.
   * Require compound literals support in the compiler at configure time.
+  * Fix compound literals usage with compilers in C99 mode, by not assigning
+    them to static variables.
 
   [ Updated dpkg translations ]
   * German (Sven Joachim).

dpkg-deb/main.c

@@ -166,7 +166,7 @@ set_deb_format(const struct cmdinfo *cip, const char *value)
 static void
 set_deb_old(const struct cmdinfo *cip, const char *value)
 {
-  deb_format = DEB_VERSION(0, 939000);
+  deb_format = DEB_VERSION_OBJECT(0, 939000);
 
   warning(_("obsolete option '--%s'; please use '--%s' instead"),
           cip->olong, "deb-format=0.939000");
@@ -175,7 +175,7 @@ set_deb_old(const struct cmdinfo *cip, const char *value)
 static void
 set_deb_new(const struct cmdinfo *cip, const char *value)
 {
-  deb_format = DEB_VERSION(2, 0);
+  deb_format = DEB_VERSION_OBJECT(2, 0);
 
   warning(_("obsolete option '--%s'; please use '--%s' instead"),
           cip->olong, "deb-format=2.0");

lib/dpkg/deb-version.h

@@ -40,10 +40,16 @@ struct deb_version {
 };
 
 /**
- * Initializer for a deb_version.
+ * Constant initializer for a deb_version.
  */
 #define DEB_VERSION(X, Y) \
-	(struct deb_version){ .major = (X), .minor = (Y) }
+	{ .major = (X), .minor = (Y) }
+
+/**
+ * Compound literal for a deb_version.
+ */
+#define DEB_VERSION_OBJECT(X, Y) \
+	(struct deb_version)DEB_VERSION(X, Y)
 
 const char *deb_version_parse(struct deb_version *version, const char *str);
 

lib/dpkg/pkg-queue.h

@@ -38,10 +38,16 @@ struct pkg_queue {
 };
 
 /**
- * Initializer for a package queue.
+ * Constant initializer for a package queue.
  */
 #define PKG_QUEUE_INIT \
-	(struct pkg_queue){ .head = NULL, .tail = NULL, .length = 0 }
+	{ .head = NULL, .tail = NULL, .length = 0 }
+
+/**
+ * Compound literal for a package queue.
+ */
+#define PKG_QUEUE_OBJECT \
+	(struct pkg_queue)PKG_QUEUE_INIT
 
 void pkg_queue_init(struct pkg_queue *queue);
 void pkg_queue_destroy(struct pkg_queue *queue);