[B.A.T.M.A.N.] [PATCH] alfred: Enable _GNU_SOURCE by default

[B.A.T.M.A.N.] [PATCH] alfred: Enable _GNU_SOURCE by default

[Sven Eckelmann]

alfred uses any netlink library which is (more or less) compatible with
libnl-3. This is for example libnl-tiny on OpenWrt.

Programs and libraries which are build against libnl-tiny must be build
with _GNU_SOURCE enabled to have some types in its headers defined. Thus
_GNU_SOURCE is enabled in the OpenWrt alfred package since 2016.3. But
sometimes using _GNU_SOURCE and sometimes not using it can have severe side
effects which are non-trivial to debug when the developer is not also using
the same _GNU_SOURCE preprocessor define. Thus enable _GNU_SOURCE by
default to have similar behavior (defines, type definitions, structure
members, ...) from headers like on OpenWrt.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 Makefile      | 1 +
 gpsd/Makefile | 1 +
 vis/Makefile  | 1 +
 3 files changed, 3 insertions(+)

diff --git a/Makefile b/Makefile
index 6daa904..552e690 100755
--- a/Makefile
+++ b/Makefile
@@ -36,6 +36,7 @@ MANPAGE = man/alfred.8
 
 # alfred flags and options
 CFLAGS += -pedantic -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP
+CPPFLAGS += -D_GNU_SOURCE
 LDLIBS += -lrt
 
 # Turn on alfred capability dropping by default - set this to n if you don't want/need it
diff --git a/gpsd/Makefile b/gpsd/Makefile
index bae5660..b6172d9 100755
--- a/gpsd/Makefile
+++ b/gpsd/Makefile
@@ -25,6 +25,7 @@ MANPAGE = man/alfred-gpsd.8
 
 # alfred flags and options
 CFLAGS += -pedantic -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP
+CPPFLAGS += -D_GNU_SOURCE
 
 # disable verbose output
 ifneq ($(findstring $(MAKEFLAGS),s),s)
diff --git a/vis/Makefile b/vis/Makefile
index fd99f49..22483a5 100755
--- a/vis/Makefile
+++ b/vis/Makefile
@@ -27,6 +27,7 @@ MANPAGE = man/batadv-vis.8
 
 # batadv-vis flags and options
 CFLAGS += -pedantic -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP
+CPPFLAGS += -D_GNU_SOURCE
 LDLIBS += -lrt
 
 # disable verbose output
-- 
2.9.3

Re: [B.A.T.M.A.N.] [PATCH] alfred: Enable _GNU_SOURCE by default

[Simon Wunderlich]

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On Friday, September 23, 2016 4:35:57 PM CEST Sven Eckelmann wrote:
> alfred uses any netlink library which is (more or less) compatible with
> libnl-3. This is for example libnl-tiny on OpenWrt.
> 
> Programs and libraries which are build against libnl-tiny must be build
> with _GNU_SOURCE enabled to have some types in its headers defined. Thus
> _GNU_SOURCE is enabled in the OpenWrt alfred package since 2016.3. But
> sometimes using _GNU_SOURCE and sometimes not using it can have severe side
> effects which are non-trivial to debug when the developer is not also using
> the same _GNU_SOURCE preprocessor define. Thus enable _GNU_SOURCE by
> default to have similar behavior (defines, type definitions, structure
> members, ...) from headers like on OpenWrt.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
Applied in revision 415ebc7

Thanks!
     Simon

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