Fix build failures with GCC 4.9+

rhbz#1307346

0001-Fix-build-with-GCC-4.9.patch

@@ -0,0 +1,72 @@
+From acd26eedac09749f82646ea1ac0a662109cca7a8 Mon Sep 17 00:00:00 2001
+From: Petr Spacek <pspacek@redhat.com>
+Date: Fri, 19 Feb 2016 13:39:27 +0100
+Subject: [PATCH] Fix build with GCC 4.9+.
+
+GCC 4.9+ is too aggressive when optimizing functions with nonnull
+attributes. This removes most of asserts() in the plugin.
+GCC 6 adds warnings for these cases.
+
+We are disabling the unwanted condition pruning by adding
+-fno-delete-null-pointer-checks argument.
+BIND 9 did the same in its commit 603a78708343f063b44affb882ef93bb19a5142a.
+
+Additionally we enable nonnull attribute only when the build is running under
+Clang static analyzer or Coverity.
+
+https://bugzilla.redhat.com/show_bug.cgi?id=1307346
+---
+ configure.ac | 14 ++++++++++++++
+ src/util.h   |  8 ++++++--
+ 2 files changed, 20 insertions(+), 2 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index a06708b1a5ee64bb64c80272c10ed1a35670c8d0..48f5cb63c3bb5535fe1da56abe7583e15d4b5f92 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -39,6 +39,20 @@ AC_TRY_COMPILE([
+ [CFLAGS="$SAVED_CFLAGS"
+  AC_MSG_RESULT([no])])
+ 
++# Check if build chain supports -fno-delete-null-pointer-checks
++# this flag avoids too agressive optimizations which would remove some asserts
++# BIND 9 did the same in its commit 603a78708343f063b44affb882ef93bb19a5142a
++AC_MSG_CHECKING([for -fno-delete-null-pointer-checks compiler flag])
++SAVED_CFLAGS="$CFLAGS"
++CFLAGS="-fno-delete-null-pointer-checks -Werror"
++AC_TRY_COMPILE([
++	extern int fdef(void);
++],[],
++[AC_MSG_RESULT([yes])
++ CFLAGS="$SAVED_CFLAGS -fno-delete-null-pointer-checks"],
++[CFLAGS="$SAVED_CFLAGS"
++ AC_MSG_RESULT([no])])
++
+ # Get CFLAGS from isc-config.sh
+ AC_ARG_VAR([BIND9_CFLAGS],
+            [C compiler flags for bind9, overriding isc-config.sh])
+diff --git a/src/util.h b/src/util.h
+index 9849ff9b6c38ec1c6dd143440d5b5e584b2ecd51..402503c339a5ab6ca5273cae420e743b9fc252ab 100644
+--- a/src/util.h
++++ b/src/util.h
+@@ -103,11 +103,15 @@ extern isc_boolean_t verbose_checks; /* from settings.c */
+ /* If no argument index list is given to the nonnull attribute,
+  * all pointer arguments are marked as non-null. */
+ #define ATTR_NONNULLS     ATTR_NONNULL()
+-#ifdef __GNUC__
++#if defined(__COVERITY__) || defined(__clang_analyzer__)
+ #define ATTR_NONNULL(...) __attribute__((nonnull(__VA_ARGS__)))
+-#define ATTR_CHECKRESULT __attribute__((warn_unused_result))
+ #else
+ #define ATTR_NONNULL(...)
++#endif
++
++#if defined(__GNUC__)
++#define ATTR_CHECKRESULT __attribute__((warn_unused_result))
++#else
+ #define ATTR_CHECKRESULT
+ #endif
+ 
+-- 
+2.5.0
+