build: Move DPKG_C_C99 call just after AC_PROG_CC

We really want subsequent checks to take advantage of the possibly set
flags to enable C99 features.

configure.ac

@@ -36,6 +36,7 @@ DPKG_DEB_COMPRESSOR([xz])
 
 # Checks for programs.
 AC_PROG_CC
+DPKG_C_C99
 AC_PROG_CXX
 AC_PROG_LEX
 DPKG_DIST_CHECK([test "$LEX" = ":"], [lex program required])
@@ -72,7 +73,6 @@ AC_C_BIGENDIAN
 AC_C_CONST
 AC_C_INLINE
 AC_C_VOLATILE
-DPKG_C_C99
 AC_TYPE_MODE_T
 AC_TYPE_PID_T
 AC_TYPE_SIZE_T

debian/changelog

@@ -2,6 +2,8 @@ dpkg (1.17.3) UNRELEASED; urgency=low
 
   * Check availability of warning flags at build time. Fixes a build failure
     on systems with old g++ compilers not accepting -Wc++11-compat.
+  * Move DPKG_C_C99 call just after AC_PROG_CC, so that subsequent checks
+    can take advantage of the possibly set flags to enable C99 features.
 
  -- Guillem Jover <guillem@debian.org>  Thu, 05 Dec 2013 06:50:31 +0100