build: Test for required compound literals

And clarify the comment on the designated initializers.

3 files changed, 8 insertions, 2 deletions

diff --git a/debian/changelog b/debian/changelog
index 3562971a7..968615665 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -71,6 +71,7 @@ dpkg (1.17.7) UNRELEASED; urgency=low
   * Set TAR preprocessor variable at build time instead of hardcoding it.
     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.
 
   [ Updated dpkg translations ]
   * German (Sven Joachim).
diff --git a/doc/coding-style.txt b/doc/coding-style.txt
index 2f18daada..3e1a30d05 100644
--- a/doc/coding-style.txt
+++ b/doc/coding-style.txt
@@ -6,7 +6,8 @@ C language extensions
 
 The code base assumes C89 plus the following C99 extensions:
 
- * Named initializers.
+ * Designated initializers.
+ * Compound literals.
  * Trailing comma in enum.
  * Variadic macros.
  * Working bool type in <stdbool.h>.
diff --git a/m4/dpkg-compiler.m4 b/m4/dpkg-compiler.m4
index f1c760bf5..84d78164e 100644
--- a/m4/dpkg-compiler.m4
+++ b/m4/dpkg-compiler.m4
@@ -125,9 +125,13 @@ AC_DEFUN([DPKG_TRY_C99],
 [[
 	int rc;
 
-	/* Compound initializers. */
+	/* Designated initializers. */
 	struct { int a, b; } foo = { .a = 1, .b = 2 };
 
+	/* Compound literals. */
+	struct point { int x, y; } p = (struct point){ .x = 0, .y = 1 };
+	p = (struct point){ .x = 2, .y = 4 };
+
 	/* Trailing comma in enum. */
 	enum { first, second, } quux;