From 37fb3503c4b1467d2b28f407b9c27c1de147869e Mon Sep 17 00:00:00 2001
From: Tuncer Ayaz <tuncer.ayaz@gmail.com>
Date: Thu, 11 Oct 2012 19:13:46 +0200
Subject: If GCC is used, treat -Wreturn-type as error

---
 lib/odbc/aclocal.m4   | 26 ++++++++++++++++++++++++++
 lib/odbc/configure.in |  5 +++++
 2 files changed, 31 insertions(+)

(limited to 'lib/odbc')

diff --git a/lib/odbc/aclocal.m4 b/lib/odbc/aclocal.m4
index 9578cd35c4..5d555a5123 100644
--- a/lib/odbc/aclocal.m4
+++ b/lib/odbc/aclocal.m4
@@ -1849,6 +1849,32 @@ case $erl_gethrvtime in
 esac
 ])dnl
 
+dnl ----------------------------------------------------------------------
+dnl
+dnl LM_TRY_ENABLE_CFLAG
+dnl
+dnl
+dnl Tries a CFLAG and sees if it can be enabled without compiler errors
+dnl $1: textual cflag to add
+dnl $2: variable to store the modified CFLAG in
+dnl Usage example LM_TRY_ENABLE_CFLAG([-Werror=return-type], [CFLAGS])
+dnl
+dnl
+AC_DEFUN([LM_TRY_ENABLE_CFLAG], [
+    AC_MSG_CHECKING([if we can add $1 to CFLAGS])
+    saved_CFLAGS=$CFLAGS;
+    CFLAGS="$1 $CFLAGS";
+    AC_TRY_COMPILE([],[return 0;],can_enable_flag=true,can_enable_flag=false)
+    CFLAGS=$saved_CFLAGS;
+    if test "X$can_enable_flag" = "Xtrue"; then
+        AC_MSG_RESULT([yes])
+        AS_VAR_SET($2, "$1 $CFLAGS")
+    else
+        AC_MSG_RESULT([no])
+        AS_VAR_SET($2, "$CFLAGS")
+    fi
+])
+
 dnl ERL_TRY_LINK_JAVA(CLASSES, FUNCTION-BODY
 dnl                   [ACTION_IF_FOUND [, ACTION-IF-NOT-FOUND]])
 dnl Freely inspired by AC_TRY_LINK. (Maybe better to create a 
diff --git a/lib/odbc/configure.in b/lib/odbc/configure.in
index bec65c71bf..e6ba9f57f5 100644
--- a/lib/odbc/configure.in
+++ b/lib/odbc/configure.in
@@ -212,4 +212,9 @@ AC_SUBST(ODBC_INCLUDE)
 
 fi dnl "$with_odbc" != "no"
 
+if test "x$GCC" = xyes; then
+    # Treat certain GCC warnings as errors
+    LM_TRY_ENABLE_CFLAG([-Werror=return-type], [CFLAGS])
+fi
+
 AC_OUTPUT(c_src/$host/Makefile:c_src/Makefile.in)
-- 
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