From 0a196219b3b4873eb882f01a374f8356061c30af Mon Sep 17 00:00:00 2001
From: Dave Beckett <dave@dajobe.org>
Date: Sun, 8 Jan 2017 13:57:31 -0800
Subject: Pull out OSX-specific and clang-specific warnings

OSX 10.2 + clang is too noisy with warnings in stdio.h
---
 configure.ac | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

(limited to 'configure.ac')

diff --git a/configure.ac b/configure.ac
index 4e63f3e1..c769f9b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -71,6 +71,13 @@ AM_PROG_AR
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_MSG_CHECKING(whether $CC is clang)
+CC_IS_CLANG=no
+if $CC 2>&1 | grep clang >/dev/null 2>&1; then
+  CC_IS_CLANG=yes
+else
+  :
+fi
+AC_MSG_RESULT($CC_IS_CLANG)
 
 dnl Initialize libtool
 LT_INIT
@@ -221,8 +228,6 @@ AC_DEFUN([REDLAND_CC_TRY_FLAG], [
 #  -Wsystem-headers   : not debugging system
 #  -Wsign-conversion: : many int / unsigned int / size_t
 #  -Wunused-parameter : variables can be marked  __attribute__('unused')
-#
-# Apple gcc specific (probably): -Wshorten-64-to-32
 possible_warnings="\
 -Wall \
 -Wc++-compat \
@@ -255,13 +260,10 @@ possible_warnings="\
 -Wsign-compare \
 -Wstrict-prototypes \
 -Wswitch-enum \
--Wundef \
 -Wunreachable-code \
 -Wunsafe-loop-optimizations \
 -Wwrite-strings \
 \
--Wshorten-64-to-32
-\
 -Wno-conversion \
 -Wno-missing-field-initializers \
 -Wno-sign-conversion \
@@ -275,6 +277,33 @@ possible_warnings="\
 -Wc99-c11-compat \
 "
 
+# compiler specific warnings
+if test $CC_IS_CLANG = yes; then
+    #  Clang
+    #  -Wno-nullability-completeness : too noisy on OSX reporting
+    #     warnings in stdio.h
+    possible_warnings="$possible_warnings \
+-Wno-nullability-completeness
+"
+fi
+
+# OS specific warnings
+case "${host_os}" in
+    darwin*)
+	# Apple gcc/clang specific:
+	#  -Wshorten-64-to-32
+	possible_warnings="$possible_warnings \
+-Wshorten-64-to-32 \
+"
+        ;;
+    *)
+	#  -Wundef : too noisy on OSX 10.12+ e.g. stdio.h fails
+	possible_warnings="$possible_warnings \
+-Wundef
+"
+	;;
+esac
+
 warning_cflags=
 if test "$USE_MAINTAINER_MODE" = yes; then
   AC_MSG_CHECKING(for supported $CC warning flags)
-- 
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