Make gnu89 support explicit

In the release/2.3 branch we support gnu89, basically to keep pre-2015 MSVC happy. Old gcc (<5) defaulted to gnu89. But gcc 5+ and clang default to gnu11/c11. This patch makes our gnu89 support explicit, such these newer compilers will also point out gnu89 violations to developers.

---
 configure.ac | 1 +
 1 file changed, 1 insertion(+)

index 62b389e..e5c7ef1 100644
@@ -1069,6 +1069,7 @@ if test "${enable_pkcs11}" = "yes"; then
 	)
 fi
 
+CFLAGS="${CFLAGS} -std=gnu89"
 if test "${enable_pedantic}" = "yes"; then
 	enable_strict="yes"
 	CFLAGS="${CFLAGS} -pedantic"

2.7.4

In the release/2.3 branch we support gnu89, basically to keep pre-2015 MSVC happy. Old gcc (<5) defaulted to gnu89. But gcc 5+ and clang default to gnu11/c11. This patch makes our gnu89 support explicit, such these newer compilers will also point out gnu89 violations to developers.

v2: only set -std=gnu89 if no -std flag is present in $CFLAGS

---
 configure.ac | 6 ++++++
 1 file changed, 6 insertions(+)

index 62b389e..af24392 100644
@@ -1069,6 +1069,12 @@ if test "${enable_pkcs11}" = "yes"; then
 	)
 fi
 
+# Set -std=gnu89 unless user already specified a -std=
+case "${CFLAGS}" in
+  *-std=*) ;;
+  *)       CFLAGS="${CFLAGS} -std=gnu89" ;;
+esac
+
 if test "${enable_pedantic}" = "yes"; then
 	enable_strict="yes"
 	CFLAGS="${CFLAGS} -pedantic"

2.7.4

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ACK. This works well on CentOS 5, so this change makes sense as this makes the compiler behaviour more predictable in regards to C standards.

This will most possibly break non-GNU compilers though (Solaris and AIX?). But as this behaviour can be overridden by setting the CFLAGS to a -std those compilers accepts, I consider this reasonable. The recommended way to set CFLAGS is like this:

     ./configure CFLAGS="-std=c99"

This ensures that if configure decides it is needed to do a re-configure run, it will preserve the CFLAGS setting.

Your patch has been applied to the release/2.3 branch.

commit 130c27b1f24a33c77e01b2cf82c3427699153967

Author: Steffan Karger
Date:   Fri Sep 16 17:40:36 2016 +0200

     Make gnu89 support explicit

     Signed-off-by: Steffan Karger <[email protected]...>
     Acked-by: David Sommerseth <[email protected]...>
     Message-Id: [email protected]...
     URL: http://www.mail-archive.com/search?l=mid&[email protected]...
     Signed-off-by: David Sommerseth <[email protected]...>

- --
kind regards,

David Sommerseth

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